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ISSN: 0852-0682 | E-ISSN: 2460-3945

Searching for Potential Multi-hazard Events during the Last 1.5 Million Years
of the Pleistocene Epoch
Balazs Bradak1,*, Christopher Gomez1, Ákos Kereszturi2, Thomas Stevens3
1

Kobe University, Japan
Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklos Astronomical Institute, Budapest, Hungary
3
Department of Earth Sciences, Uppsala University, Sweden
2

*)

Correspondence: bradak.b.@port.kobe-u.ac.jp

Citation:
Bradak, B., Gomez, C., Kereszturi, Á., &

Abstract

Stevens, T. (2022). Searching for potential

Increasing attention has been paid to multi-hazards in environmental disaster studies produced during the
last decade. Multi-hazard studies focus on the occurrence, interaction and effect of several natural hazards
in the same region. Despite the increasing number of multi-hazard studies, few investigations have focused
on global-scale multi-hazard events. With the aim of closing this gap, our study focuses on the identification
of periods during the last 1.5 million years of the Pleistocene epoch, with the quasi-parallel appearance of
natural hazards (e.g., asteroid impacts and large volcanic eruptions with a Volcanic Explosivity Index (VEI)
of 8 and 7) amplifying their individual effects and thus causing long-term, global-scale changes. Of the seven
identified potential multi-hazard events, three were considered as possible global-scale events with a longer
term environmental (paleoclimatic) impact; dated to c.a., 1.4 Ma (marine isotope stage – MIS45), 1.0 Ma
(MIS 27), and 100 ka (MIS 5c), respectively. Two additional periods (around 50 and 20 ka) were identified
as being associated with more restricted scale multi-hazard events, which might cause a “Little Ice Age-like”
climatic episode in the history of the Pleistocene Period. In addition, we present a hypothesis about the
complex climatic response to a global-scale multi-hazard event consisting of a series of asteroid impacts and
volcanic eruption linked to a geomagnetic polarity change, namely the Matuyama-Brunhes Boundary, which
might be accompanied by global cooling and result in the final step of the Early Middle Pleistocene Transition.
Keywords: multi-hazard; global-scale event; asteroid impact; supervolcano eruption; geomagnetic field fluctuation.

multi-hazard events during the last 1.5
million years of the Pleistocene epoch. Forum Geografi, 36(1).

Article history:
Received: 21 October 2021
Accepted: 28 March 2022
Published: 08 August 2022

1. Introduction
The multi-hazard approach, a relatively new subfield in hazard research, is defined as an “approach that considers more than one hazard in a given place (ideally progressing to consider all
known hazards) and the interrelations between these hazards, including their simultaneous or cumulative occurrence and their potential interactions” (Gill et al., 2016; http://www.interactinghazards.com/defining-multi-hazard). However, the amplifying events need to happen close in
time to each other to lead to a joint consequence and, in the case of global effects, do not necessarily need to happen spatially close to each other.
As Gill and Malamud (2014) and Gill et al. (2016) summarised, the term “multi-hazard” is used
in multiple ways: i) the overlay of single (discrete and independent) hazards; ii) the identification
of all hazards in one place; and iii) the identification of all hazards in one place and description
of the interaction which may occur between them.
Despite the increasing number of multi-hazard studies that focus mainly on the local and regional
scale, few studies have focused on global-scale, multi-hazard events. Although extending such
scale to the continental or global level is an exciting and possibly necessary step, it seems speculative from many angles. Despite the occurrence of certain events, such as the famous eruption of
the Krakatau volcano (1883), or the Tohoku Oki earthquake and tsunami (2011), which both had
continental and/or global-scale implications and a devastating regional-scale effect, no or only
short-term (in a geological sense) global-scale consequences ensued. The lack of a long-term
global-scale effect by present day (in a historical time sense) natural hazards is definitely fortunate
from the perspective of, for example, the civilization and society, but it removes the opportunity
for scientists to support their theories and models with observations.
Copyright: © 2022 by the authors. Submitted for possible open access publication under the terms and conditions of
the Creative Commons Attribution (CC
BY) license (https://creativecommons.org/licenses/by/4.0/).

Bradak et al.

Turning to the study of the geological past to gain information about the possible effect of globalscale multi-hazards may produce new information about the characteristics and magnitude of such
events but, despite the rising availability of datasets and increasing number of case studies, potential multi-hazard events have rarely been studied in detail to date (one exception may be the
Chicxulub impact event, a likely cause of the Cretaceous-Paleogene extinction event; see Renne
et al., 2013, and the references therein).

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The aim of this study is to reveal a potential chain of stochastic global-scale catastrophic multihazard events and describe their possible influence. Due to the limitation of the existing datasets
and lack of information about the early geological period, this study focuses on events that occurred during the last 1.5 million years of the Pleistocene epoch (from 10 ka to 1.5 Ma), as these
recent events are not unique on the geological timescales and they might even emerge in modern
times.
The studied period consists of the so-called Early Middle Pleistocene Transition (EMPT), the
great global reorganisation of climate/climate cyclicity, from marine isotope stage (MIS) 20 to
MIS18 (~850 to 650 ka) (e.g., Heslop et al., 2002). Undertaking a comparison of the timing of the
global-scale hazard events and switch in the length of climate cycles during the EMPT will enable
us to build a novel hypothesis: that the effect and superposition of stochastic geological events,
such as a series of meteorite impacts, supervolcano eruptions and weakening of the magnetic field,
trigger climatic instability and accelerate the accumulation of ice sheets. Under this scenario, these
geological events act as ‘catalysts’ of climatic instability and push the system toward a threshold
by strengthening the global cooling tendencies.

2. Research Method
Information about various terrestrial impacts was collected from the Earth Impact Database (EID,
2018) and the corresponding literature, listed in the references. In some cases, due to the lack of
an independent, accurate numerical age estimate, the maximum age of the event was used. The
latest, most reliable calculation of impact frequencies in the near-Earth region is that provided by
Stuart and Binzel (2004), in which the impact of a 1 km or larger object on the Earth is estimated,
with a frequency of once every 0.60±0.1 Myr (releasing 1021 J of energy), and also the impact of
a 200 m diameter asteroid once every 56,000±6000 yr (releasing 4×1018 J total energy). To estimate the size of the asteroid, the following equation, provided by Hughes (2003), was used:

log D (km) = (1.026 ± 0.5) + (1.16 ± 0.04) × log d (km)

(1)

where, D is the size of the impact crater, and d the estimated size of the asteroid.
The estimation of the impact energy is based on the following equation, provided by Hughes
(2003):

E (erg) = 9.1 × 1024D2.59

(2)

Where, D is the diameter of the impact crater (km).
A larger impact may cause a significant earthquake, characterized by its estimated magnitude (M),
and the area of influence (A), following the calculations proposed by Bath (1981) and Toon et al.
(1997):

M = 0.7 × log(εe × Y) + 7.2

(3)

Where, M is the magnitude of the earthquake, Y(=E) is the kinetic energy of the object (in Mt)
and εe is defined as 10-4, a constant, representing the efficiency of the conversion of kinetic energy by the impactor into elastic wave energy in the earthquake, calculated for a typical broken
and fractured crustal rock:

A (km2) = 3 × 109 × {10-0.63I × (εe × Y)0.63}-h2

(4)

The relationship in this equation between the impactor energy and the area affected by the triggered earthquake is quasi-independent of h (epicenter of the earthquake in km), assuming that the
depth is of the order of 10 km (Toon et al., 1997).
The reference chart in Table 1 summarizes the key, updated information obtained from the literature on the influence of asteroid impacts, based on the estimated size of the impactor (for additional information, please see the caption to Table 1).
Table 1. Summary of the impact events by scale and their related consequences (after Marcus et al. 2010).
More detailed information can be found about the additional influence of impacts in various studies, such as
Artemieva and Morgan (2017; gas release due to impacts), Kring et al. (1995), Pope et al. (1997) (effects of
impact-released sulphur content on ozone), Butchart and Scaife (2001; how decreased ozone concentration
modifies the adsorption of solar energy though the atmospheric column), Haruma et al. (2007; the link
between an impact in the ocean and decreasing ozone), Pierazzo et al. (2010; estimating the decrease in

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ozone content occasioned by a 0.5-1 km diameter impactor), and Ermakov et al. (2009; impacts and
thunderstorms).
Name of event
type
Chelyabinsk
category events
(c.a. 20 m)
Tunguska category events
(c.a., 80-100 m)

General consequences
Ionospheric disturbances for hours

Probability or period
of occurrence
10-50 years

Consequences on
climate change
Probably unobservable

Dust injection into
the atmosphere, ionospheric disturbances

1,000 years

Impact of 200 m
category objects

107 ton dust injection
into the atmosphere,
ionospheric disturbances, “rain of fire”,
impact crater formation with 3 km diameter, some NOx
generation
108 ton dust (109 ton
H2O in the case of
ocean impact) injection into the atmosphere, ionospheric
disturbances, impact
crater formation
with a 7-8 km diameter, NOx generation
109 ton dust (in the
case of ocean 1010 ton
H2O) impact injection into the atmosphere, ionospheric
disturbances, impact
crater formation
with a 14 km diameter, NOx generation

56,000 years

Minor, potentially
observable in an
ideal case, but
without any longterm global consequences
Observable cooling
effect

Impact of 500 m
category objects

Impact of 1000
m category objects

120,000 years

Probably globally
observable consequences in the temperature records

600,000 years

Definitely globally
observable consequences with substantial temperature deviation,
might reach the
bottom of the shallow ocean

Information from the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database concerning various volcanic eruptions was collected and analysed (Crosweller et al., 2012; Brown et
al., 2014). During the search for possible multi-hazard events, Volcanic Explosivity Index (VEI)
8 and 7 volcanic eruptions were considered as a possible cause of global-scale, longer-term
changes, based on the work of, e.g., Rampino (2002) and Newhall et al. (2018). Although there
remains no agreement about the environmental influence of individual VEI 8 and 7 eruptions (e.g.,
the Late Pleistocene Toba supervolcano eruption), increasing evidence is coming to light of the
long-term climatic influence of the series of volcanic eruptions even on the geological timescale
(e.g., Ward, 2009; Newhall et al., 2018; Sorenghan et al., 2019).
As Rampino (2002) summarized, there exist many similarities between asteroid impacts and
large-scale volcanic eruptions, so our study’s primary focus is on the identification of multi-hazard events consisting of asteroid impacts and VEI≥7 volcanic eruptions. Fluctuations in the geomagnetic field can be observed from the changes in relative paleointensity, preserved in various
geological records. In this study, VADM (Virtual Axial Dipole Moment) data from Channell et
al. (2009) (PISO-1500) and Guyodo and Valet (1999) (Sint-800) were used. Relative paleointensity data were used to indicate the weakening of the geomagnetic field, which may have contributed to climate change. Although there are many concerns about the phenomenon, the weakening
of the geomagnetic field appears around events such as magnetic polarity change (e.g., at the
Matuyama Brunhes Boundary - MBB), which leads to an increase in the galactic cosmic ray

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(GCR) flux and exerts some degree of influence on the paleoclimate. The growing GCR may
increase the low-level cloud (Swensmark effect; Svensmark and Friis-Christensen 1997) which,
in turn, increases the albedo effect and decreases the temperature. This is referred to as the Umbrella effect (e.g., Kitaba et al. 2017). Due to its expected influence on climate together with the
overlapping of magnetic polarity change and asteroid impacts, the Umbrella effect may be defined
as contributing to the cause of unusual palaeoclimatic events and so is included in the study. As
we suggested above, there are many concerns about the influence of the weak geomagnetic field
and growing GCR on the climate. The pros and cons of these phenomena are summarized in
Section 3.3.1 in detail.

3. Results and Discussion
3.1. Identification of possible multi-hazard events in the last 1.5 Ma and their evaluation
Based on the analysed datasets, seven almost overlapping events were recognized as overlapping
potential multi-hazard events in the last 1.5 Ma of the Pleistocene Period (Figure 1a, and Table
2). Among the seven events, the ~1.4 Ma (MIS 45), ~1Ma (MIS 27) and ~100 ka (MIS 5c) events
consist of asteroid impacts (MIS 45, and 5c) and a series of supervolcano (VEI 8; MIS 27), and/or
large volcanic eruptions (VEI 7; MIS 45, and 5c), and seem to have exerted a global-scale influence through the combined effect of the asteroid impact, series of large or supervolcano eruptions
(category VEI7 and 8), and, in a particular case (the ~100 ka event), the weakening of the geomagnetic field during the so-called Post Blake event (Singer et al., 2014).

Figure 1. Overlapping asteroid impact, volcanic eruption and geomagnetic polarity change events in the last
1.5 Ma of the Pleistocene (Holocene excluded) (a): the past ~1.4 Ma multi-hazard event (b); the past ~1.0
Ma multi-hazard event (c); the past ~300 and 270 ka multi-hazard events (d); and the past ~100, ~50, and
~20 ka multi-hazard events (e). About the identified events please find additional information in Table 2.
The red circles mark known asteroid impacts, the grey triangles indicate VEI7 and 8 volcanic eruptions, and
the dotted-dashed lines mark geomagnetic polarity changes (excursions and reversals), respectively. The
magnetostratigraphy of the studied period is shown in Figure 1a, with the normal and reverse geomagnetic
polarity indicated by black and white sections, respectively (based on Cande and Kent, 1995; Laj and Channel, 2007). Excursions on Figure 1a: 1-Hilina Pali; 2-Mono Lake; 3-Laschamp;4-Norwegian-Greenland Sea;
5-Post Blake; 6-Blake; 7-Iceland Basin; 8-Pringle Falls; 9-Calabrian Ridge 0; 10-Calabrian Ridge I; 11-

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Laguna del Sello; 12-Un-named; 13-Calabrian Ridge II; 14-West Eifel 5; 15-Big Lost; 16-West Eifel 4; 17West Eifel 2; 18-Stage 17; 19-West Eifel 1; 20-MBB Reversal; 21-MBB Precursor; 22-Kamikatsura; 23Santa Rosa; 24-Jaramillo; 25-Jaramillo Pre; 26-Punaruru; 27-Cobb Mtn.; 28-Bjorn; 29-Meseta del Lago
(Buenos Aires); 30-Gardar.
Table 2. A comparison of the quasi-parallel environmental disasters in the last 1.5 Ma of the Pleistocene
Period, including asteroid impacts, large and supervolcano eruptions and the change in the geomagnetic
field. ^-impact with potential global influence (e.g., global cooling), based on Toon et al. (1997); * - potential
VEI 8 supervolcano eruption (based on the LaMEVE data from Crosweller et al., 2012) ¤ - observable
cooling effect, based on the impactor size (see Table 1). Events marked in “bold” (in the first column of
Table 2) are identified as multi-hazard events with a global-scale and possibly longer-term effect. Events in
normal script might have a globally recognizable effect, with a short-term influence. Events marked in italics
are those with a stronger local and/or regional influence, but weak or negligible global-scale influence on
the paleoenvironment. An MIS abbreviation with a number refers to the Marine Isotope Stages (odd number
– interglacial; even number – glacial periods). In the case of MIS 5c, c indicates a shorter warmer period
during the interglacial era. Please find additional studies about the listed impacts and eruptions at Earth
Impact Database (http://passc.net/EarthImpactDatabase/New%20website_05-2018/Index.html) and the
Natural Global Volcanism Program (National Museum of Natural History, Smithsonian Institution, USA;
https://volcano.si.edu/), respectively.

The ~100ka (MIS 5c)
multi-hazard event
(Fig.1e)

The ~270ka (MIS
8) multi-hazard
event (Fig. 1d)

The ~300ka (MIS 9-8
trans.) multi-hazard
event (Fig. 1d)

The ~1 Ma (MIS 27)
multi-hazard event
(Fig. 1c)

The ~1.4 Ma (MIS
45) multi-hazard
(Fig. 1b)

M-h.
event

Bradak et al.

Impact
crater

Pingualuit^,
¤ (New
Quebec)

Montura
qui
(Australia)
Veevers
(Australia)

Wolfe
Creek
(Australia)

Dalgaranga
(Australia)
Agoudal
(105 ka;
Morocco) ¤
Rio
Cuarto^,
¤ (100
ka; Argentina)

Volcanic eruption
(VEI 7 and 8)

Taisetsuzan (Japan);
Hodakadake (Japan)
Mangakino (New
Zealand)

Mangakino*(New
Zealand); Corbetti
Caldera* (Ethiopia);
Yabakei caldera*
(Shishimuta cal., Japan); TokachiMitsumata (Japan)

Calabozos (Chile)
Vulsini (Italy)

Kapenga (New Zealand); Aso (Japan)

Toya (105 ka; Japan);
Vulsini (100ka; Italy);
Emmons Lake (96ka;
USA)

E (Mt)

Eq
(M)

Eq A
(×104
km2)

5.3×103

7.0

7.7

2.9×10

5.4

2.9

3.1×10-1

4.0

1.2

1.5×102

5.9

4.0

1.4×10-2

3.1

0.7

3.7×103

6.9

7.2

1.1×104

7.2

8.8

Short evaluation of the event
The impact might cause observable cooling on a global-scale
(Table 1, and Toon et al.,1997);
the overlapping impact and series of VEI7 volcanic eruptions,
possibly triggered long term climate change ("small ice ages")
(Ward, 2009; Newhall et al.,
2018).
The global influence of the impacts may be negligible, but the
recorded three super- and two
large volcanic eruptions might
exert a significant influence on
the climate and environment
(e.g., Rampino, 2002; Ward,
2009; Newhall et al., 2018;
Sorenghan et al. 2019).
Concerns about the chronometric age and global influence of
the impact, as well as the two
eruptions, compared to the magnitude of other events.

The impactor size and energy
seem too small to cause globalscale disasters; the volcanic
eruptions might cause observable changes on a global-scale
e.g., short-term cooling
(Newhall et al., 2018).
The overlapping of a series of
asteroid impacts with considerable size and impact magnitude
possibly caused global changes
(Table 1; and Toon et al.,
1997), along with the three VEI
7 volcano eruptions (Ward,
2009; Newhall et al., 2018), and
weakening of the geomagnetic
field (Post-Blake event; Fig.
1e).

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The ~20ka
(MIS 2) multihazard event
(Fig. 1e)

The ~50ka (MIS 3)
multi-hazard event (Fig.
1e)

Table 2. Continued

Amguid
(100 ka;
Algeria)
Lonar
(52ka;
India) ¤
Xiuyan
(50ka;
China) ¤
Barringer
(49ka;
USA)
Tenoumer¤
(21.4
ka;
Mauritania)

Ischia (58 ka; Italy);
Maninjau (52ka; Indonesia); Campi Flegrei (50ka; Italy)
Nemo Peak (45ka;
Kuril Island)

Opala (22ka; Kamchatka Island); Zavaritsky (20ka; Kamchatka Island); Lon
Island (19.245ka;
New Guinea)

2.7×10

5.4

2.9

1.0×103

6.5

5.7

1.0×103

6.5

5.6

3.4×102

6.2

4.6

1.1×103

6.5

5.8

The asteroid impacts might
cause globally observable,
shorter-term cooling, which environmental influence was possibly reinforced by four VEI7
large volcanic eruptions (Ward,
2009; Newhall et al., 2018).
The asteroid impact might exert
a globally recognizable, shortterm effect (Table1), strengthened by the series of VEI 7 volcanic eruptions (Newhall et al.,
2018).

The events date back to the Late Pleistocene Period; namely, the ~100ka (MIS5c), ~50ka (MIS
3), and ~20ka (MIS 2) multi-hazard events, consist of overlapping series of asteroid impacts and
VEI 7 volcanic eruptions. Although the potential global influence of such multi-hazard events is
less than the three events suggested above (MIS45, 27 and 5c), they might cause observable
shorter-term (e.g., Little Ice Age-like) global environmental changes (Figure 1e and Table 2).
There are two multi-hazard events, which might have negligible global effects, compared to the
other five. The asteroid impacts and volcanic eruptions may exert a significant local/regional influence during the ~300 ka, and ~270 ka events but, due to the magnitude of the impact events,
might not cause any global-scale longer-term environmental changes (Figure 1d and Table 2).

3.2. Some segments of the global-scale influence of multi-hazard events
Three to five possible multi-hazard events were recognized in the last 1.5 Ma years of the Pleistocene Period, the influence of which will be briefly reviewed in the following.
Toon et al. (1997) provided a detailed description of the influence of the impacts, based on their
energy and influence on the environment. The study defines asteroids ranging in size from c.a.
850 m to 1.4 km, with a 104-105 Mt impact energy, as the smallest which may have a global
influence due to the stratospheric water vapor injection, dust load to the atmosphere, and ozone
loss. This impact energy level may have been reached in two cases in our list: namely, during the
Pingualuit (~1.4 Ma, MIS45) and Rio Cuarto (~100 ka; MIS 5c) impact events. Other events are
considered smaller impact events, with local and/or regional effects only.
Rampino (2002) compared supervolcano eruptions (supereruptions) to asteroid impacts. The
study suggests that supereruptions produce >1000 km3 of ejected material, inject ≥1000 Mt aerosols and submicron size dust into the atmosphere, and are capable of creating global climatic
disturbance, similar to the influence of an impact by an asteroid measuring ≥1 km in diameter.
Based on the studied datasets, the concomitant appearance of such eruptions, combined with asteroid impacts at a local and regional scale, happened during MIS 27 (~ 1 Ma).
As the example of the MIS 27 above demonstrates, the data mining for this study did not simply
focus on individual events, but the sequencef and/or overlapping of possibly larger-scale hazards
(multi-hazard events). As the study of Ward (2009) suggests, the effect of individual (“sporadic”)
large volcanic eruptions may be cooling due to the sulfuric acid formation in the lower atmosphere. The study suggests that the series (sequence) of such eruptions may push the climate into
an “ice age”. The findings of Soreghan et al. (2019) are in line with those of Ward (2009): frequent
explosive volcanism can sustain icehouse conditions due to, e.g., the increasing atmospheric acidity, and the ash and dust that are injeceted into the atmosphere. Such conditions, with a series of
large (VEI7 and 8) volcanic eruptions, may apply throughout the period covered by this study.
It seems important to highlight that long-term, global-scale paleoenvironmental influence/changes
tend to happen following the appearance of a series or sequences of (overlapping) events,

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compared to individual eruptions or impacts that occurred during the studied period. There might
be some exceptions, such as the eruption of Toba volcano during the Late Pleistocene Period (c.a.
70 ka ago), but the existence of the long-term effect (producing a widespread glaciation period)
of the Toba “mega-eruption” continues to spark ongoing scientific arguments (e.g., Rampino and
Self, 1992, 1993a, 1993b; Zielinski et al., 1996; Oppenheimer, 2002; Robock et al., 2009).
Besides the role of a series of impact events and volcanic eruptions in triggering longer-term
global-scale (paleo)climatic changes by strengthening each other influence, there is one additional
connection between asteroid impacts and volcanic activity to be considered. The studies of Watt
et al. (2009) and Namiki et al. (2016) suggest that there exists a connection between larger earthquakes and volcanic eruptions, triggered by dynamic and static stress, and stress-related processes,
associated with the earthquakes. Although the estimated timescale of a triggered volcanic eruption
is only several months, we believe that it is worth mentioning the possible connection between an
impact triggered ≥7M earthquake (e.g., in the case of the studied impacts: Pingualuit and Rio
Cuarto impactors) and volcanic activity.

3.3. Some thoughts about “hidden” global-scale catastrophic multi-hazard events
As shown in Figures 1 and 2, there exists a significant gap in the number of asteroid impacts in
the studied period, especially between 900 and 300 ka during the early Middle Pleistocene Period.
As demonstrated in Figure 2, a considerable number of estimated asteroid impacts are “missing”,
probably due to various reasons. The lack of a known impact crater does not necessarily mean the
lack of an impact event as, e.g., i) the impact crater may simply not have been discovered yet, or
its existence may not have been verified by various studies (e.g., a recently discovered Pantasma
crater from the early Middle Pleistocene Period, Rochette et al., 2019); ii) some terrestrial impact
craters may be covered by various substances (e.g., continental ice; Kjær et al., 2018); iii) impacts
in the marine environment could still have happened which, e.g., turbidity currents would cover
(e.g., the Eltanin impact). The Eltanin impact provides a useful reference point for the examination
of the potential influence of a meteorite impact on longer-term climate transitions and changes,
being one of the suggested climatic drivers marking the Pliocene/Pleistocene boundary (Gisler et
al., 2011; Goff et al., 2012). Signs of a meteorite impact, such as the presence of anomalous
amounts of iridium, sedimentary disturbance, and changes in the environment, were discovered
and reported in drilling cores (Bellinghausen Sea, Eastern Pacific Southern Ocean) by Gersonde
et al. (1997), Colodner et al. (1981), and Ward and Asphaug (2002). Based on high-resolution
bio-, and magnetostratigraphical investigations, the impact event is dated to ~2.511±0.07 Ma. The
impacting body was 1-4 km diameter, and its impact energy ranged from 105 to 107 Mt. It would
have left a 35 km diameter crater, though this has yet to be identified (Kyte et al., 1988). This
asteroid possibly caused environmental change on a global-scale, including a mega-tsunami and
the destabilization of the Antarctic ice shelf area (Gersonde et al. 2005). As already suggested
above, it served as a climatic driver of the Plio-Pleistocene transition.

Figure 2. The identified terrestrial and possible unidentified impacts of the last 1.5 Ma of the Pleistocene
Period. Identified (black dots) and expected and unidentified impacts (white dots) according to the size and

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age of the craters, based on the Earth Impact Database: http://www.passc.net/EarthImpactDatabase. Based
on the size distribution of the impactors (known from astronomical surveys (Heinze et al., 2021) and crater
size frequency distribution on the Moon (Fassett, 2016), it can be estimated how many craters should be
observable on the Earth due to recent impacts (Hergarten and Kenkmann, 2015). extracting this from the
number of observed ones, the values for the "missing" ones arises. The red area indicates the studied
timeframe, between 10 ka and 1.5 Ma.).

In general, according to the calculations, the impact of a 500 m diameter asteroid in the marine
environment could inject 1,011 tons of water into the atmosphere (Gisler et al., 2003). Such an
event may well have happened more than once in the last million years. The impact of a 1 km
diameter asteroid produces a global level of ozone destruction comparable to the so-called ozone
hole discovered in the 1990s, while a 500 m body’s impact results in ozone depletion confined
mainly to a half hemisphere (Pierazo et al., 2010). In this particular case, the Eltanin impact might
eject a large amount of water vapour and salt into the atmosphere, thereby increasing the albedo
effect, depleting the ozone layer and causing surface acidification by sulphur and vaporized water
(Goff et al., 2012). Although the suggested time period for the impact overlaps the Pliocene/Pleistocene climate transition, an event marked by major glaciation in the Northern Hemisphere, the
cooling effect of such an impact remains questionable; i.e., the atmospheric H2O along with dust
might trigger either warming (via the greenhouse effect) or cooling (brought about by ice clouds).
The Eltanin event is not only useful as a reference point for understanding the long-term climate
influence of an asteroid impact but also a starting point for understanding the problems related to
investigating the effect of an impact in a marine environment. Among the around 170 known
impact craters, only 15-20 are found in a marine environment (Shuvalov and Trubestkaya, 2002),
partly because of the general relative youth of the oceanic lithosphere, combined with a lack of
detailed knowledge about the sea floor. Using theoretical calculations and laboratory tests (Davison and Collins, 2007), it has been estimated that craters of around ten times the diameter of the
impactor could be vaporized into the ocean water. In theory, in the last 100 million years, about
150 impacts in oceans would have produced 5-20 km diameter craters. About two-thirds of the
<1 km diameter craters can be studied on the ocean floor, and about one-third of 30 km diameter
craters, too. For example, in the case of the Eltanin impact, not a crater but only a chaotically
mixed region could be identified in the Bellingshaisen Sea (Gersonde, 1997). A relatively recent
event of this type is the so-called 4 kyr BP impact, that has long been confused with a climatic or
volcanic event (Courty et al., 2007). This event was recently identified as the impact (or a multiimpact event), in which at least part of the impact in object hit water-covered areas.

3.3.1. A chain of stochastic events during the Early Middle Pleistocene Transition –
a case study
Orbital forcing is accepted as the driver behind the multi-millennial climate cyclicity of the Pleistocene period climatic cycles generally. Such cyclicity has a characteristic switch around the early
Middle Pleistocene period, described as EMPT, the great global reorganisation of climate including some characteristic steps from MIS 20 to MIS18 (~850 to 650 ka) (Heslop et al., 2002) (Figure
3). However, the cause of the shift from dominant 40 kyr to 100 kyr oscillations and increase in
oscillation amplitude at the EMPT is not yet understood. It is especially critical to determine this,
as the shift to 100 kyr high amplitude cycles is not marked by a corresponding change in orbital
forcing, and the 100 kyr orbital cycle is the weakest cycle in terms of affecting the amount of
insolation received at the Earth’s surface (Maslin and Brierly, 2015). This 100 kyr cycle dominance in the post EMPT climate is often referred to as the ‘100 ka paradox’, as no explanation for
this has been agreed upon. A key theory argues that the EMPT was caused by changing the internal response of the global carbon cycle to orbital forcing. This change allowed increased ice sheet
growth in the Northern Hemisphere, preventing obliquity-driven increased heat transport northward from melting them (Maslin and Brierly, 2015). A recent model describes the transition as
“ramping with frequency locking” (RFL; Nyman and Ditlevsen, 2019); i.e., the periodicity change
can be characterized by a long-term (ca. 1Ma) transition, in which the periodicity changes gradually (from a 40 to 80 ka period over one million years). However, this transition period consists
of shorter frequency locking periods (no change in periodicity), separated by jumps (Figure 3b).
Although the model provides a novel explanation about the nature of the EMPT, the mechanism
behind the “jumps” between the frequency locking phases have not been fully explained. This
means that a fundamental component for understanding this transition is unknown. The model
emphasizes the rapid change in atmospheric CO2 as a potential driver of the jumps and the EMPT,
but there is no physical explanation behind this theory.

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Figure 3. The characteristics of EMPT (after, Mudelsee and Stattegger, 1997; Maslin and Brierly, 2015; and
Nyman and Ditlevsen, 2019). a) The results of a time-series analysis of δ18O (ice volume) data and orbital
parameters. Based on model a), the EMPT is indicated by a transition in the time-dependent mean (the upper
blue bar) toward higher ice volumes (higher δ18O values). The time series analysis indicates a ca. 200 ka
long delay (the difference between the two blue bars, marked by a red double-ended arrow) between the
significant increase in the global ice volume and the switch between the 41 and 100 ka periods, indicated by
the time-dependent std (the lower blue bar). The delay includes the period of overlapping stochastic events
(the red bar and vertical dotted and dashed lines). Based on model b), the EMPT is a gradual change, which
consists of frequency locking phases and rapid jumps, representing changing climate variables driving the
EMPT or its consequences (Nyman and Ditlevsen, 2019). Some of the rapid jumps seems to be connected
to the stochastic geological events (red bar and vertical lines), appearing in the studied timeframe (MIS2018) (for a detailed explanation, see Figure 4 and Section 3.3.1). The various curves on the diagram indicate
the average duration between glacial terminations, calculated by various mathematical methods (Nyman and
Ditlevsen, 2019). Both models a) and b) consist of a key period (a – delay; b – jump) that has not been
explained yet and may be connected to the appearance of stochastic geological events.

Our research proposes a novel hypothesis: the superposition of random geological events (see
below) drives the climate system to reach a threshold where the periodicity switch or the suggested
jumps in frequency occur (Figure 3 and 4). Some theories already suggest a threshold-driven
switch but, besides the model, no convincing explanation has been provided (Maslin and Brierly,
2015). A series of meteorite impacts, including ones with potential global influence, have been
identified at the same time as the EMPT (~850 to 680 ka), as indicated by the Belize tektite/Pantasma impact (Rochette et al., 2019) and the Australasian strewn field (Prasad et al., 2007;
Schwartz et al., 2016; Sieh et al., 2020; and the references therein) (Figure 3 and 4, I[I] and II[II]).
Based on the size of the strewn field, and the possible impact crater(s), the estimated energy of
the meteorite impacts was sufficient to exert severe global effects (Earth Impact Effects Program
– Marcus et al., 2004 and Collins et al., 2010; and Toon et al., 1997). Furthermore, the first supervolcano eruption of Toba occurred closet to the EMPT and might also have strengthened the
influence of these meteorite impacts (Lee et al., 2004) (Figure 4, T). Indeed, both meteorite
strikes, and volcanic eruptions can cause significant cooling (e.g., McCormic et al., 1995; Toon
et al., 1997; Rampino, 2002; Ward, 2009; Soreghan et al., 2019). Firstly, dust injection into the
atmosphere modifies the albedo by affecting the cloud coverage via an elevated number of condensation nuclei (Saunders et al., 2007). Secondly, the atmospheric loading of submicron size
aerosols caused by an impact or eruption can cause a “volcanic winter” via direct radiative forcing
effects, with a global cooling of 3-5°C and regional cooling of up to 15°C (Rampino, 2002). The
cooling triggered by the overlapping stochastic events may cause the “rapid jump” (which, based
on the model indicates rapid climatic change, but has no physical explanation yet), and appears in

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the RFL model at around 800-750 ka, immediately prior to the stabilization of the ca. 100 ka
climatic period (Nyman and Ditlevsen, 2019) (Figure 3b).

Figure 4. The appearance of the stochastic geological events during the final step of EMPT. The known
impact events (a) and VEI8 and 7 scale volcanic eruptions (b) are indicated by I, [I]-Australites, Indochinites
and Western Canadian tektite and II-Belize impact (785±7 ka and 769±16 ka) (Prasad et al., 2007; Schwarz
et al., 2016; Rochette et al., 2019; III-Luochuan tektite (Li et al., 1993; Zhou and Shackleton, 1999). The
pink/red areas (e, that also appear in Figure 3b) indicate the potential appearance of meteoritic materials with
the potential impacts (I-III) and supervolcano-, (grey triangles, based on VOGRIPA-Volcanic Global Risk
Identification and Analysis Project database); e.g., the Long Valley (LV) eruption (c.a., 760 ka) and Toba
(T) eruption (788±2.2 ka) (Lee et al., 2004). The impact events are indicated by the Australasian strewn field
(australites and indochinites), Western Canadian tektite (Schwarz et al., 2016) and the Belize impact glass
(Prasad et al., 2007). The australites are dated to 789 ± 9 ka, while the age of the indochinites is 783 ± 5 ka,
the Western Canadian tektites 783 ± 17 ka, and the Belize tektite/Pantasma impact seems to have happened
around 769 ± 16 ka (Schwarz et al., 2016) or 815 ± 11 ka ago (Rochette et al., 2019). No clear impact crater
of the proposed Australasian impact event has yet convincingly been identified (e.g., Glass and Koeberl
2006; Prasad et al., 2007; Mizera et al., 2016; Sieh et al., 2020; and the references therein). There are two
additional types of geological events which might have strengthened the influence of any multiple meteorite
impact in the time period of the EMPT. The Toba (Indonesia, Sumatra, 788 ± 2.2 ka; Lee et al., 2004) and
the Long Valley (Bishop Tuff, USA, California, ~760 ka; Smithsonian Pleistocene Database, 2010)
supervolcano eruptions happened after the Australasian impact. The change in the geomagnetic field is
indicated by the VADM (Virtual Axial Dipole Moment) data from Channell et al. (2009) (dark grey curve;
PISO-1500) and Guyodo and Valet (1999) (light grey curve; Sint-800) (c). MBB - Matuyama Brunhes
Boundary (778±1.7 - Tauxe et al. 1996; 770±7.3 - Suganuma et al., 2015). Marine 18O curve (d) is from
Ferretti et al. (2015).

In addition to the chain of asteroid impacts and supervolcano eruption, the increasing cosmic ray
flux, associated with the weakening of the geomagnetic field, might exert an observable influence
on the (paleo)climate, as suggested by the Svensmark theory (Svensmark and Friis-Christensen,
1997). The climatic influence might appear during the period of geomagnetic change, such as the
Matuyama/Jaramillo and Matuyama/Brunhes geomagnetic polarity reversals (Kitaba et al., 2013,
and 2017). During the Matuyama-Brunhes geomagnetic reversal (Matuyama-Brunhes Transition,
MBT)—the overlapping period of the chain of asteroid impacts and the supervolcano eruption
suggested above—, the weakening of the geomagnetic field led to an increase in the GCR flux.

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The growing GCR may increase low-level clouds (Svensmark hypothesis), which increases the
albedo and decreases the temperature. This is called the Umbrella effect, and its climatic influence, i.e., ∼6 to 9 °C cooling of the global climate, has already been identified in various records
(Kitaba et al., 2017). In the loess profile of the Chinese Loess Plateau (CLP), which is a commonly
used terrestrial record, the intensification of the East Asian winter monsoon and cooling were
observed during MIS19 around the MBT, which suggests the appearance of the Umbrella effect
(Ueno et al., 2019).
Despite the study of Marsh and Svensmark (2000), which describes the connection between cosmic ray flux and cloud formation and the possible evidence from various geological sections
(Kitaba et al., 2013; Ueno et al., 2019), the relevance of this theory has been questioned by various
studies, such as Sloan and Wolfendale (2008) and Erlykin and Wolfendale (2011). Although the
described physical mechanism behind the cloud formation is plausible (Tinsley, 2000; Svensmark
et al., 2009), it has not yet been established (Wagner et al., 2001; Pierce and Adams, 2009), and
the results of models that aimed to verify or deny the theory are still insufficiently convincing
(Duplissy et al., 2010, Kirkby et al., 2011). Despite the studies of Kitaba et al. (2013, 2017) and
Ueno et al. (2019), no direct connection has been found between the fluctuation of the magnetic
field and the paleoclimate (Suganuma et al., 2018), and even the existence of the long-term climatic influence of the galactic cosmic ray flux has been questioned as well (Lanci et al., 2020).
However, whilst compelling, detailed evidence to support this possibility is currently lacking, the
analysis of the markers of the stochastic events for this period has not been fully conducted yet,
and further results are needed (e.g., computer simulations, geological and geomorphological studies, etc.).

4. Conclusion
During the last decade, an increasing amount of attention has been paid to multi-hazards in environmental disaster studies. Despite the increasing number of multi-hazard studies, the majority
focus on the appearance, interaction and effect of natural hazards in the same region. There is
considerably less investigation of global-scale, multi-hazard events and their potential global climatic impact. Seeking to closing this gap, our study focused on the identification of periods in the
last 1.5 million year of the Pleistocene epoch, with the quasi-parallel appearance of natural hazards; i.e., asteroid impacts and large, VEI 8 and 7 volcanic eruptions with the potential to trigger
long-term global-scale paleoenvironmental changes.
Of the seven potential multi-hazard events identified, three were considered as possible globalscale events with a lo3nger term environmental (paleoclimatic) influence, which dated back to
c.a. 1.4 (marine isotope stage – MIS45), 1.0 Ma (MIS 27), and 100 ka (MIS 5c), respectively.
Two additional periods, (around 50ka – MIS3; and 20 ka – MIS2), were identified as being linked
to multi-hazard events, which might have caused the “Little Ice Age (or stadial)-like” climatic
episode during the Late Pleistocene period.
In addition to the identified potential multi-hazards, a theory about the complex climatic response
to global-scale, multi-hazard events, which consists of a series of asteroid impacts and volcanic
eruption, was introduced. The series of events, accompanied by possible global cooling appearing
around a geomagnetic polarity change, namely the Matuyama-Brunhes Boundary, might have
contributed to the final cooling step of the Early Middle Pleistocene Transition, a period during
which the length of the glacial-interglacial periods shifted from dominant 40 kyr to 100 kyr oscillations.
We believe that our study may function as a “starting line” for studies focusing on a detailed
investigation of “paleo multi-hazard events”, assigned by our data-mining approach. Such studies
may reveal more paleoenvironmental-paleoclimatic information and build new theories about
multi-hazard events in the future.

References
Artemieva, N., Morgan, J. (2017). Quantifying the release of climate‐active gases by large meteorite impacts with a case
study of Chicxulub, Geophysical Research Letters Vol. 44, pp. 10180-10188. https://doi.org/10.1002/2017GL074879
Bath, M. (1981). Earthquake magnitude-Recent research and current trends, Earth Sci. Rev., Vol. 17, pp. 315-398.
https://doi.org/10.1016/0012-8252(81)90014-3
Brown, S.K., Crosweller, H.S., Sparks, R.S.J., Cottrell, E., Deligne, N.I., Guerrero, N.O., Hobbs, L., Kiyosugi, K., Loughlin, S.C., Siebert, L., Takarada, S. (2014). Characterisation of the Quaternary eruption record: Analysis of the Large

Bradak et al.

Page 49

Forum Geografi, 36(1), 2022; DOI: 10.23917/forgeo.v36i1.16093
Magnitude Explosive Volcanic Eruptions (LaMEVE) database, Journal of Applied Volcanology Vol. 3, 5,
doi:10.1186/2191-5040-3-5.
Butchart, N., Scaife, A.A. (2001), Removal of chlorofluorocarbons by increased mass exchange between the stratosphere
and troposphere in a changing climate, Nature Vol. 410, pp. 799-802. https://doi.org/10.1038/35071047
Cande, S.C., Kent, D.V. (1995), Revised calibration of the geomagnetic polarity timescale for the late Cretaceous and
Cenozoic, J. Geophys. Res., Vol. 100, pp. 6093-6095. https://doi.org/10.1029/94JB03098
Collins, G.S., Melosh, H.J.,Marcus, R.A. (2005), Earth Impact Effects Program: A Web-based computer program for
calculating the regional environmental consequences of a meteoroid impact on Earth, Meteoritics & Planetary Science,
Vol. 40, pp. 817-840. https://doi.org/10.1111/j.1945-5100.2005.tb00157.x
Colodner, D.C., Boyle, E.A., Edmond, J.M., Thomson, J. (1981), Post-depositional mobility of platinum, iridium and
rhenium in marine sediments, Nature Vol. 292, pp. 417-420, https://doi.org/10.1038/358402a0
Courty, M. A., Giuseppe, C., Crisci, A., Crosta, X., De Wever, P., Fedoroff, M., Guichard, F., Mermoux, M., Smith, D.
and Thiemens, M. H. (2007), Impact fingerprints of the 4 kyr BP dust event based on archaeological, soil, lake and marine
archives , Geophysical Research Abstracts, European Geosciences Union (EGU) General Assembly 2007, April 15th20th, Wien (Austria), https://epic.awi.de/id/eprint/16964/
Crosweller, H.S., Arora, B., Brown, S.K., Cottrell, E., Deligne, N.I., Guerrero, N.O., Hobbs, L., Kiyosugi, K., Loughlin,
S.C., Lowndes, J., Nayembil, M., Siebert, L., Sparks, R.S.J., Takarada, S., Venzke, E. (2012), Global database on large
magnitude explosive volcanic eruptions (LaMEVE), J Appl. Volcanol. Vol. 1, 4. https://doi.org/10.1186/2191-5040-1-4
Channell, J.E.T., Xuan, C., Hodell, D.A. (2009), Stacking paleointensity and oxygen isotope data for the last 1.5 Myr
(PISO-1500), Earth and Planetary Science Letters Vol. 283, pp. 14-23, https://doi.org/10.1016/j.epsl.2009.03.012
Davison, T. and Collins, G.S. (2007), The effect of the oceans on the terrestrial crater size-frequency distribution: Insight
from numerical modeling. Meteoritics & Planetary Science Vol. 42, pp. 1915-1927. https://doi.org/10.1111/j.19455100.2007.tb00550.x
Duplissy, J., Enghoff, M. B., Aplin, K. L., Arnold, F., Aufmhoff, H., Avngaard, M., Baltensperger, U., Bondo, T., Bingham, R., Carslaw, K., Curtius, J., David, A., Fastrup, B., Gagné, S., Hahn, F., Harrison, R. G., Kellett, B., Kirkby, J.,
Kulmala, M., Laakso, L., Laaksonen, A., Lillestol, E., Lockwood, M., Mäkelä, J., Makhmutov, V., Marsh, N. D., Nieminen, T., Onnela, A., Pedersen, E., Pedersen, J. O. P., Polny, J., Reichl, U., Seinfeld, J. H., Sipilä, M., Stozhkov, Y., Stratmann, F., Svensmark, H., Svensmark, J., Veenhof, R., Verheggen, B., Viisanen, Y., Wagner, P. E., Wehrle, G., Weingartner, E., Wex, H., Wilhelmsson, M., Winkler, P. M. (2010), Results from the CERN pilot CLOUD experiment, Atmos.
Chem. Phys., Vol.10, pp. 1635–1647, https://doi.org/10.5194/acp-10-1635-2010, 2010.
EID. (2018), Earth Impact Database: http://www.passc.net/EarthImpactDatabase (EID, 2018)
Erlykin, A.D., Wolfendale, A.W. (2011), Cosmic ray effects on cloud cover and their relevance to climate change, Journal
of Atmospheric and Solar-Terrestrial Physics Vol. 73, No. 13, pp. 1681-1686. https://doi.org/10.1016/j.jastp.2011.03.001
Ermakov, I., Okhlopkov, V.P., Stozhkov, Y.I. (2009), The Impact of Cosmic Dust on the Earth’s Climate, Vestnik Moskovskogo Universiteta. Fizika Vol. 2, pp. 104-106.
Fassett, C. I. (2016), Analysis of impact crater populations and the geochronology of planetary surfaces in the inner solar
system,
Journal
of
Geophysical
Research:
Planets
Vol.
121,
No.
10,
pp.
1900-1926,
https://doi.org/10.1002/2016JE005094.
Ferretti, P., Crowhurst, S.J., David, B., Barbante, C. (2015), The Marine Isotope Stage 19 in the mid-latitude North Atlantic Ocean: astronomical signature and intra-interglacial variability. Quaternary Science Reviews, Vol. 108, pp. 95-110.
https://doi.org/10.1016/j.quascirev.2014.10.024
Gersonde. R., Kyte, F.T., Bleil, U., Diekmann, B., Flores, J.A., Gohl, K., Grahl, G., Hagen, R., Kuhn, G., Sierro, F.J.,
Völker, D., Abelmann, A., Bostwick, J.A. (1997), Gersonde et al. Geological record and reconstruction of the late Pliocene
impact of the Eltanin asteroid in the Southern Ocean, Nature Vol. 390, pp. 357-363. https://doi.org/10.1038/37044
Gersonde, R., Kyte, F.T., Frederichs, T., Bleil, U., Schenke, H-W., Kuhn, G. (2005), The late Pliocene impact of the
Eltanin asteroid into the Southern Ocean – Documentation and environmental consequences, Geophysical Research Abstracts Vol. 7: 02449, SRef-ID: 1607-7962/gra/EGU05-A-02449.
Gill, J., Duncan, M., Budimir, M. (2016), Defining Multi-Hazard, The dynamics and impacts of interacting natural hazards. http://www.interactinghazards.com/defining-multi-hazard
Gill, J. C., Malamud, B. D. (2014), Reviewing and visualizing the interactions of natural hazards, Reviews of Geophysics
Vol. 52, No. 4, pp. 680-722. https://doi.org/10.1002/2013RG000445
Gisler, G., Weaver, R., Gittings, M. (2011), Calculations of asteroid impacts into deep and shallow water, Pure and Applied Geophysics Vol. 168, pp. 1187-1198. https://doi.org/10.1007/s00024-010-0225-7
Glass, B.P. and Koeberl, C. (2006), Australasian microtektites and associated impact ejecta in the South China Sea and
the Middle Pleistocene supereruption of Toba. Meteoritics & Planetary Science Vol. 41, pp. 305-326.
https://doi.org/10.1111/j.1945-5100.2006.tb00211.x
Goff, J., Chagué-Goff, C., Archer, M., Dominey-Howes, D., Turney, C. (2012), The Eltanin asteroid impact: possible
South Pacific palaeomegatsunami footprint and potential implications for the Pliocene–Pleistocene transition, Journal of
Quaternary Science Vol. 27, pp. 660-670. https://doi.org/10.1002/jqs.2571
Guyodo, Y., Valet, J-P. (1999), Global changes in intensity of the Earth’s magnetic field during the past 800kyr, Nature,
Vol. 399, pp. 249-252. https://doi.org/10.1038/20420

Bradak et al.

Page 50

Forum Geografi, 36(1), 2022; DOI: 10.23917/forgeo.v36i1.16093
Haruma, I., Kunio, K., Shoji, A. (2007), Effects of a large asteroid impact on ultra-violet radiation in the atmosphere,
Geophysical Research Letters Vol. 34, L23805. https://doi.org/10.1029/2007GL030697
Heinze, A. N.; Denneau, L., Tonry, J. L., Smartt, S. J., Erasmus, N., Fitzsimmons, A., Robinson, J. E., Weiland, H.,
Flewelling, H., Stalder, B., Rest, A., Young, D. R. (2021), NEO Population, Velocity Bias, and Impact Risk from an
ATLAS Analysis, The Planetary Science Journal Vol. 2/1, id.12, 17 pp. https://doi.org/10.3847/PSJ/abd325
Hergarten, S. ; Kenkmann, T. (2015), The number of impact craters on Earth: Any room for further discoveries? Earth
and Planetary Science Letters Vol. 425, pp. 187-192. https://doi.org/10.1016/j.epsl.2015.06.009
Heslop, D., Dekkers, M.J., Langeresi, C.G. (2002), Timing and structure of the mid-Pleistocene transition: records from
the loess deposits of northern China, Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 185, pp. 133-143.
https://doi.org/10.1016/S0031-0182(02)00282-1
Hughes, D.W. (2003), The approximate ratios between the diameters of terrestrial impact craters and the causative incident
asteroids, Mon. Not. R. Astron. Soc. Vol. 338, pp. 999–1003. https://doi.org/10.1046/j.1365-8711.2003.06157.x
Kitaba, I., Hyodo, M., Katoh, S., Dettman, D.L., Sato, H. (2013), Midlatitude cooling caused by geomagnetic field minimum during polarity reversal, PNAS Vol. 110, pp. 1215-1220. https://doi.org/10.1073/pnas.1213389110
Kitaba, I., Hyodo, M., Nakagawa, T., Katoh, S., Dettman, D.L., Sato, H. (2017), Geological support for the Umbrella
Effect as a link between geomagnetic field and climate, Scientific Reports 7:40682, https://doi.org/10.1038/srep40682
Kjær, K.H., Larsen, N.K., Binder, T., Bjørk, A.A., Eisen, O., Fahnestock, M.A., Funder, S., Garde, A.A., Haack, H., Helm,
V. and Houmark-Nielsen, M., (2018). A large impact crater beneath Hiawatha Glacier in northwest Greenland. Science
advances Vol .4(11), p.eaar8173. DOI: 10.1126/sciadv.aar8173
Kring, D.A., Melosh, H.J., Hunten, D.M. (1995), Possible climatic perturbations produced by impacting asteroids and
comets, Meteoritics Vol. 30, pp. 530-550.
Kirkby, J., Curtius, J., Almeida, J., Dunne, E., Duplissy, J., Ehrhart, S., Franchin, A., Gagné, S., Ickes, L., Kürten, A.,
Kupc, A., Metzger, A., Riccobono, F., Rondo, L., Schobesberger, S., Tsagkogeorgas, G., Wimmer, D., Amorim, A., Bianchi, F., Breitenlechner, M., David, A., Dommen, J., Downard, A., Ehn, M., Flagan, R.C., Haider, S., Hansel, A., Hauser,
D., Jud, W., Junninen, H., Kreissl, F., Kvashin, A., Laaksonen, A., Lehtipalo, K., Lima, J., Lovejoy, E.R., Makhmutov,
V., Mathot, S., Mikkilä, J., Minginette, P., Mogo, S., Nieminen, T., Onnela, A., Pereira, P., Petäjä, T., Schnitzhofer, R.,
Seinfeld, J.H., Sipilä, M., Stozhkov, Y., Stratmann, F., Tomé, A., Vanhanen, J., Viisanen, Y., Vrtala, A., Wagner, P.E.,
Walther, H., Weingartner, E., Wex, H., Winkler, P.M., Carslaw, K.S., Worsnop, D.R., Baltensperger, U., Kulmala, M.
(2011), Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation, Nature Vol. 476, pp.
429–433. https://doi.org/10.1038/nature10343
Kyte, F.T., Zhou, L., Wasson, J.T. (1988), New evidence on the size and possible effects of a late Pliocene oceanic impact,
Science Vol. 241, pp. 63-65. doi: 10.1126/science.241.4861.63. PMID: 17815539.
Laj, C., Channell, J.E.T., (2007), Geomagnetic excursions, in: Kono, M. (ed.), Treatise on Geophysics, vol. 5, Geomagnetism, Elsevier, Amsterdam, pp. 373–416.
Lanci, L., Galeotti, S., Grimani, C., Huber, M. (2020), Evidence against a long-term control on Earth climate by Galactic
Cosmic Ray Flux, Global and Planetary Change Vol. 185, January 2020, 103095 https://doi.org/10.1016/j.gloplacha.2019.103095
Lee, M-Y., Chen, C-H., Wei, K-Y., Iizuka, Y., Carey, S. (2004), First Toba supereruption revival, Geology Vol. 32, No.1,
pp. 61–64. https://doi.org/10.1130/G19903.1
Li, C-L., Ouyang, Z-Y., Liu, D-S., An, Z-S. (1993), Microtektites and glassy microspherules in loess: their discoveries
and implications, Science in China (Series B) Vol. 36, pp. 1141-1153.
Marcus,R.H., Melosh, J., Collins, G. (2004), Earth Impact Effects Program. (Imperial College London / Purdue University) https://impact.ese.ic.ac.uk/ImpactEarth/ImpactEffects/.
Marsh, N., Svensmark, H. (2000), Cosmic Rays, Clouds, and Climate, Space Science Reviews Vol. 94, pp. 215–230.
https://doi.org/10.1023/A:1026723423896
Maslin, M. A, Brierly, C. M. (2015), The role of orbital forcing in the Early Middle Pleistocene Transition, Quaternary
International Vol. 389, pp. 47-55. https://doi.org/10.1016/j.quaint.2015.01.047
McCormick, M. P., Thomason, L. W., Trepte, C. R. (1995), Atmospheric effects of the Mt Pinatubo eruption, Nature Vol.
373, pp. 399-404. https://doi.org/10.1038/373399a0
Mizera, J., Řanda, Z. and Kameník, J. (2016), On a possible parent crater for Australasian tektites: Geochemical, isotopic,
geographical and other constraints. Earth-Science Reviews Vol. 154, pp.123-137. https://doi.org/10.1016/j.earscirev.2015.12.004
Mohr, P. A., Mitchell, J. G., Raynolds, R. G. H. (1980), Quaternary volcanism and faulting at O'A caldera, central Ethiopian Rift, Bull Volcanol Vol. 43, 173-190. https://doi.org/10.1007/BF02597619
Mudelsee, M., Stattegger, K. (1997), Exploring the structure of the mid-Pleistocene revolution with advanced methods of
time-series analysis, International Journal of Earth Sciences/Geologiche Rundschau Vol. 86, pp. 499-511.
https://doi.org/10.1007/s005310050157
Nyman, K.H.M. and Ditlevsen, P.D. (2019), The middle Pleistocene transition by frequency locking and slow ramping of
internal period, Climate Dynamics Vol. 53, pp. 3023–3038. https://doi.org/10.1007/s00382-019-04679-3

Bradak et al.

Page 51

Forum Geografi, 36(1), 2022; DOI: 10.23917/forgeo.v36i1.16093
Namiki, A., Rivalta, E., With, H., Walter, T. R. (2016), Sloshing of a bubbly magma reservoir as a mechanism of triggered
eruptions, Journal of Volcanology and Geothermal Research Vol. 320, pp. 156–171. https://doi.org/10.1016/j.jvolgeores.2016.03.010
Newhall, C. G., Self, S. (1982), The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical
volcanism, J. Geophys. Res. Vol. 87 (C2), pp. 1231–1238. https://doi.org/10.1029/JC087iC02p01231
Newhall, C., Self, S., Robock, A. (2018), Anticipating future Volcanic Explosivity Index (VEI) 7 eruptions and their
chilling impacts, Geosphere Vol. 14, No. 2, pp. 572–603. doi: https://doi.org/10.1130/GES01513.1
Oppenheimer, C. (2002), Limited global change due to largest known Quaternary eruption, Toba ≈74 kyr BP?, Quaternary
Science Reviews Vol. 21, No. 14–15, pp. 1593–1609. https://doi.org/10.1016/S0277-3791(01)00154-8
Pierazzo, E., Garcia, R.R., Kinnison, D.E., Marsh, D.R., Lee-Taylor, J., Crutzen, P.J. (2010), Ozone perturbation from
medium-size asteroid impacts in the ocean, Earth and Planetary Science Letters Vol. 299, pp. 263-272.
https://doi.org/10.1016/j.epsl.2010.08.036
Pierce, J.R. and Adams, P.J. (2009), Can cosmic rays affect cloud condensation nuclei by altering new particle formation
rates? Geophys Res Lett Vol. 36, L09820, https://doi.org/10.1029/2009GL037946
Pope, K.O., Baines, K.H., Ocampo, A.C., Ivanov, B.A. (1997), Energy, volatile production, and climatic effects of the
Chicxulub Cretaceous/Tertiary impact, Journal of Geophysical Research Vol. 102(E9), pp. 21645-21664.
https://doi.org/10.1029/97JE01743
Prasad, M. S., Mahale, V. P., Kodagali, V. N. (2007), New sites of Australasian microtektites in the central Indian Ocean:
Implications for the location and size of source crater, J. Geophys. Res. Vol. 112, E06007,
https://doi.org/10.1029/2006JE002857.
Rampino, M.R. (2002), Supereruptions as a threat to civilizations on Earth-like planets, Icarus Vol. 156, pp. 562-569.
https://doi.org/10.1006/icar.2001.6808
Rampino, M. R.; Self, S. (1992), Volcanic winter and accelerated glaciation following the Toba Super-eruption, Nature
Vol. 359 (6390), pp. 50–52. https://doi.org/10.1038/359050a0
Rampino, M. R., Self, S. (1993a), Climate–volcanism feedback and the Toba Eruption of ~74,000 Years ago", Quaternary
Research Vol. 40, No. 3, pp. 269–280. https://doi.org/10.1006/qres.1993.1081
Rampino, M. R., Self, S. (1993b), Bottleneck in the Human Evolution and the Toba Eruption, Science Vol. 262 (5142),
1955. DOI: 10.1126/science.8266085
Renne, P.R., Deino, A.L., Hilgen, F.J., Kuiper, K.F., Mark, D.F., Smit, J. (2013), Time Scales of Critical Events Around
the Cretaceous-Paleogene Boundary, Science Vol. 339, pp. 684-687. DOI: 10.1126/science.1230492
Robock, A.; Ammann, C.M.; Oman, L.; Shindell, D.; Levis, S.; Stenchikov, G. (2009), Did the Toba volcanic eruption of
~74k BP produce widespread glaciation? Journal of Geophysical Research Vol. 114 (D10): D10107.
https://doi.org/10.1029/2008JD011652
Rochette, P., Alaç, R., Beck, P., Brocard, G., Cavosie, A. J., Debaille, V., Devouard, B. et al. (2019). Pantasma: A Pleistocene Circa 14 km Diameter Impact Crater in Nicaragua. Meteoritics & Planetary Science Vol. 54. pp. 880– 901.
https://doi.org/10.1111/maps.13244
Saunders RW, Forster PM, Plane JMP. (2007), Potential climatic effects of meteoric smoke in the Earth’s paleo-atmosphere, Geophysical Research Letters Vol. 34: L16801. https://doi.org/10.1029/2007GL029648
Schwarz, W.H., Trieloff, M., Bollinger, K., Gantert, N., Fernandes, V.A., Meyer, H-P., Povenmire, H., Jessberger, E.K.,
Guglielmino, M., Koeberl, C. (2016), Coeval ages of Australasian, Central American and Western Canadian tektites reveal
multiple impacts 790 ka ago, Geochimica et Cosmochimica Acta Vol. 178, pp. 307–319.
https://doi.org/10.1016/j.gca.2015.12.037
Shuvalov, V.V., Trubestkaya, I.A. (2002). Numerical Modeling of Marine Target Impacts. Solar System Research Vol.
36, pp. 417–430. https://doi.org/10.1023/A:1020467522340
Sieh, K., Herrin, J., Jicha, B.,Angel, D. S., Moore, J.D.P., Banerjee, P., Wiwegwin, W., Sihavong, V., Singer, B., Chualawanich, T., Charusiri, P. (2020), Australasian impact crater buried under the Bolaven volcanic field, Southern Laos,
PNAS Vol. 117, pp. 1346–1353. https://doi.org/10.1073/pnas.1904368116
Singer, B.S., Guillou, H., Jicha, B.R., Zanella, E., Camps, P. (2014), Refining the Quaternary Geomagnetic Instability
Time Scale (GITS): Lava flow recordings of the Blake and Post-Blake excursions, Quaternary Geochronology Vol. 21,
pp. 16-28. https://doi.org/10.1016/j.quageo.2012.12.005
Sloan, T., Wolfendale, A.W. (2013), Cosmic rays, solar activity and the climate, Environ. Res. Lett. Vol. 8, 045022.
https://doi.org/10.1088/1748-9326/8/4/045022
Soreghan, G.S., Soreghan, M.J., Heavens, N.G. (2019), Explosive volcanism as a key driver of the late Paleozoic ice age,
Geology Vol. 47, pp. 600–604, https:// doi .org /10 .1130 /G46349.1
Stuart, J.S, Binzel, R.P. (2004), Bias-corrected population, size distribution, and impact hazard for the near-Earth objects,
Icarus Vol. 170, pp. 295-311. https://doi.org/10.1016/j.icarus.2004.03.018
Suganuma, Y., Okada, M., Horie, K., Kaiden, H., Takehara, M., Senda, R., Kimura, J.-I., Kawamura, K., Haneda, Y.,
Kazaoka, O., Head, M. J. (2015), Age of Matuyama-Brunhes boundary constrained by U–Pb zircon dating of a widespread
tephra, Geology Vol. 43, pp. 491–494. https://doi.org/10.1130/G36625.1

Bradak et al.

Page 52

Forum Geografi, 36(1), 2022; DOI: 10.23917/forgeo.v36i1.16093
Suganuma,Y., Haneda,Y., Kameo,K., Kubota,Y., Hayashi,H., Itaki,T., Okuda,M., Head,M.J., Sugaya,M., Nakazato,H.,
Igarashi,A., Shikoku,K., Hongo,M., Watanabe, M., Satoguchi,Y., Takeshita,Y., Nishida,N., Izumi,K., Kawamura,K., Kawamata,M., Okuno,J., Yoshida,T., Ogitsu, I., Yabusaki, H., Okada, M. (2018), Paleoclimatic and paleoceanographic records through Marine Isotope Stage 19 at the Chiba composite section, central Japan: A key reference for the Early–Middle
Pleistocene Subseries boundary, Quaternary Science Reviews Vol. 191, pp. 406-430. https://doi.org/10.1016/j.quascirev.2018.04.022.
Svensmark, H., Friis-Christensen, E. (1997), Variation of cosmic ray flux and global cloud coverage—a missing link in
solar-climate relationships, Journal of Atmospheric and Solar-Terrestrial Physics Vol. 59, No. 11, pp. 1225-1232.
https://doi.org/10.1016/S1364-6826(97)00001-1
Svensmark, H., Bondo, T. and Svensmark, J. (2009), Cosmic ray decreases affect atmospheric aerosols and clouds, Geophys Res Lett Vol. 36, L15101. https://doi.org/10.1029/2009GL038429
Ueno,Y., Hyodo, M.,Yang, T., Katoh, S. (2019), Intensified East Asian winter monsoon during the last geomagnetic
reversal transition, Scientific Reports Vol.9:9389. https://doi.org/10.1038/s41598-019-45466-8
Tauxe, L., Herbert, T., Shackleton, N. J., Kok, Y. S. (1996), Astronomical calibration of the Matuyama-Brunhes boundary:
consequences for magnetic remnance acquisition in marine carbonates and the Asian loess sequences, Earth Planet. Sci.
Lett. Vol. 140, pp. 133–146. https://doi.org/10.1016/0012-821X(96)00030-1
Tinsley, B.A. (2000), Influence of solar wind on the global electric circuit, and inferred effects on cloud microphysics,
temperature, and dynamics in the troposphere,
Space Sci Rev
Vol. 94, pp. 231–258.
https://doi.org/10.1023/A:1026775408875
Toon, O. B., Zahnle, K., Morrison, D., Turco, R. P., Covey, C. (1997), Environmental perturbations caused by the impacts
of asteroids and comets, Rev. Geophys., Vol. 35(1), pp. 41– 78. https://doi.org/10.1029/96RG030
Wagner, G., Livingstone, D.M., Masarik, J., Muscheler, R., Beer, J. (2001), Some results relevant to the discussion of a
possible link between cosmic rays and Earth’s climate, J Geophys Res Vol. 106, pp. 3381–3387.
https://doi.org/10.1029/2000JD900589
Ward, L. P. (2009), Sulfur dioxide initiates global climate change in four ways, Thin Solid Films Vol. 517, pp. 3188–
3203. https://doi.org/10.1016/j.tsf.2009.01.005
Ward, S.N., Asphaug, E. (2002), Impact tsunami–Eltanin, Deep-Sea Research Part II. Topical Studies in Oceanography
Vol. 49, No. 6, pp. 1073-1079. https://doi.org/10.1016/S0967-0645(01)00147-3
Watt, S.F.L., Pyle, D.M., Mather, T.A. (2009), The influence of great earthquakes on volcanic eruption rate along the
Chilean
subduction
zone,
Earth and
Planetary
Science
Letters
Vol.
277,
pp. 399–407.
https://doi.org/10.1016/j.epsl.2008.11.005
Zhou, L.P., Shackleton, N.J. (1999), Misleading positions of geomagnetic reversal boundaries in Eurasian loess and implications for correlation between continental and marine sedimentary sequences, Earth and Planetary Science Letters
Vol. 168, pp. 117–130. https://doi.org/10.1016/S0012-821X(99)00052-7
Zielinski, G. A., Mayewski, P. A., Meeker, L. D., Whitlow, S., Twickler, M.S., Taylor, K. (1996), Potential atmospheric
impact of the Toba Mega-Eruption ∼71,000 years ago, Geophysical Research Letters Vol. 23, No. 8, pp. 837-840.
https://doi.org/10.1029/96GL00706

Bradak et al.

Page 53