Indonesian Journal of Geography.
Vol 54.
No.
ISSN 2354-9114 .
ISSN 0024-9521 .
Indonesian Journal of Geography Vol 57.
No.
: 495-505
DOI: 10.
22146/ijg.
94996 website: htps://jurnal.
id/ijg A2025 Faculty of Geography UGM and The Indonesian Geographers Association ARTICLEARTICLE
REVIEW
RESEARCH
Flood Risk Mapping Using GISReduction and Multi-Criteria Analysis at Coast Nanga Pinoh West Challenges of Tsunami Risk on the Serang West Kalimantan Area Novian Andri Akhirianto1.
Dwi Abad Tiwi2.
Astisiasari2.
Ahmad Pratama Putra2.
Raditya Panji Umbara2.
Achmad Fakhrus Shomim1,2Rustam .
Deliyanti Ganesha33,Dony and Enggar
Utari44
*Ajun Purwanto
Eviliyanto
Andrasmoro
1,3,4
Research Center for Hydrodynamics Technology.
National Research and Innovation Agency.
Yogyakarta.
Indonesia.
Departmen of Geography Education IKIP PGRI Pontianak Research Center for Geological Disaster.
National and Innovation Agency.
Tangerang Selatan.
Indonesia.
Departmen of Counseling Guidance Education IKIPResearch PGRI Pontianak Directorate of Regional Research and Innovation Policy.
National Research and Innovation Agency.
Jakarta.
Indonesia.
Center for Environmental Research and Disaster Mitigation Studies.
Sultan Ageng Tirtayasa University.
Serang.
Indonesia Received: 2021-12-22 Abstract.
Flood is one of the disasters that often hit various regions in Indonesia, specifically in West Kalimantan.
Accepted: 2022-10-13 The floods in Nanga Pinoh District.
Melawi Regency, submerged 18 villages and thousands of houses.
Therefore, this study aimed to map flood risk areas in Nanga Pinoh and their environmental impact.
Secondary data on slope.
The soil that type,was cover from with earthquakes the multi-criteria Abstract.
Sunda Strait hit theGIS Received: 2024-03-20 Keywords:
The Serang Regency Flood Risk.
GIS,
Multi-Criteria Revised:
2024-05-03
and lowthe riskDisaster class areRisk 1,515.
ha, 30,194.
ha, 21,953.
ha, and Reduction (DRR) This Analysis.
Nanga Pinoh Accepted: 2025-12-03 These the GIS approach multi-criteria are identify for flood the DRR that has after theand tsunami, and Published: 2025-12-04 helpful in anticipating greater input factors, as valuable on enhancing the tsunami resilience.
This research has a qualitative descriptive study, using primary and secondary data sources.
The data collection A2022 by the authors.
Licensee Indonesian Journal of Geography.
Indonesia.
*Correspondeny email:
FGDs, and field observations.
Furthermore, this study This article is an openemploy access articlethe under the terms and conditions of the Creative Commons ajunpurwanto@ikippgriptk.
Attribution(CC BY NC) licensehttps://creativecommons.
org/licenses/by-nc/4.
applies SWOT analysis to identify the internal and external environmental factors.
The results indicate the Key words: tsunami.
progresses made in tsunami DRR on the west coast of Serang Regency.
However, although policies for coastal disaster risk reduction.
area planning and management have been established, there is still a need for community socialization, proper implementation, and enforcement of theintensity Moreover, of robustareas early warning systemThis Sunda Strait.
Serang in theboth of West Kalimantan.
Introductin on vandalism is also needed.
Finally, the Pinoh results Police of identifying the internal Regency within the Nanga Floods occur when a riverpublic its storage external environmental factors show that Tanjung there are Lay 3 strengths.
Village.
Tembawang Panjang.
Pal Village.
Tanjung forcing the excess water to overflow the banks and fill the Accordingly, the results of this identification can be used to formulate advance strategies in increasing the Niaga.
Kenual.
Baru and Sidomulyo Village in Nanga Pinoh adjacent low-lying lands.
Thistsunami resilience on the west coast of Serang Regency.
Spectacle.
Melawi Regency (Supriyadi, 2.
most frequent disasters affecting a majority of countries Correspondent The flood disaster in Melawi Regency should be mitigated worldwide (Rincyn et: al.
, 2018.
Zwenzner Voigt.
A2025 by the authors and Indonesian Journal of Geography novi014@brin.
mapping the risk.
an open article distributed the termsfuture and conditions of the Creativeby Commons specifically Indonesia.
FloodingThis is one Attribution(CC BY NC) licensehttps://creativecommons.
org/licenses/by-nc/4.
Various technologies such as Remote Sensing and Geographic disasters that yearly damage natural and man-made Information Systems have been developed for monitoring flood (Du et al.
, 2013.
Falguni & Singh, 2020.
Tehrany et al.
, 2013.
This technology has significantly contributed to flood Youssef et al.
, 2.
monitoring and for the (Takabatake et al.
Mount Krakatau is one of the are flood risks in many regions resulting in great There Introduction (Biswajeet Mardiana.
Haqa in Indonesia.
In 1883,&its eruption triggered et al.
, tsunami Mahmoud & Gan.
The (Alfieri Sunda Strait on December 22,2.
2018, with et al.
, 2012.
Pradhan , 2.
caused et
36,000
deaths Furthermore, and 297 damaged and earthquakes.
tectonics nor The impacts have been flood vulnerability and as (BMKG.
Maheldatoetmap , 2.
Sea water raised (Falguni & Singh.
Geographic.
Komolafe et al.
the eruption of Mount Anak Krakatau.
These m on the damage.
edge of the Sunda Strait, 4 mguide on the Rincyn , 2018.
Skilodimou et al.
, 2.
Thetsunami did not receive (RS) and Geographic Systems of Remote Sumatra Sensing Island, 2-2.
m on the northInformation and south coasts include loss of human et on the population, (Syamsidik ,adverse Anak Krakatau Mountain (GIS)Island, to improve of monitoring and managing Java in the Pacific Ocean to South America to theStrait essential services, the Sunda released volcaniclastic flood disasters (Haq et al.
according to Ponangsera (Soloviev & Go.
Moreover, the spread a tsunami withofa height of up to water 13 meters on adjacent the ageapart of modern et alIn.
, from the volcanic activity of Mount Anak (Rincyn et in al.
Java2.
and Sumatra (Grilli et al.
, 2.
The tsunami extracted through Geographical Information SystemStrait (GIS) also Krakatau, the hazard of tsunamis in the Sunda Food accounts 40%no of global at night for Remotefrom Sensing (RS) into provides tremendous the Megathrust in quantity (Lyu et high , 2019.
PetitThus, which caused monitoring, and assessing flood in thefor Sunda Strait segment.
Boix et al.
,injuries, 2.
, with damages increasing in the areasignificantly around the (Biswajeet Mardiana.
Haq are et al.
the lastand decades(Sabara (Komolafe , 2020.
Sunda Straitin(Banten Lampun.
et al.
,et2.
The Tsunamis generated by material 2009.
Pradhan Understanding Rozalis et , in TheProvince factors include causingPandeglang floods include Banten known by the public, even though they occur and is essential in making climateRegencies, change (Ozkan Zhou include et al.
, 2.
Serang in Tarhan.
Lampung Province South (Paris aetcomprehensive , 2.
The hazard of a tsunami Different land structure (Jha et al.
Zwenzner & Voigt,(Widiyanto 2.
, and Lampung.
Tanggamus Pesawaran Regencies the Sunda Straithazard needs attention, the Sunda areasAo (Curebal , 2.
, 2.
This tsunami a total of 437etfatalities.
Strait has an important role locally and globally.
The Sunda Theserole for and Other causes land-use as deforestation 31,943are 16,198 such people (BNPB.
Strait a major in connecting of Java urbanization (Huong & Pathirana, 2013.
Rincyn et al.
, 2018.
Sumatra, which have 77.
7 % of IndonesiaAos population (BPSmitigatingIndonesia, future floods, and implementing Zhang et al.
,volcano Zhou , 2.
Statistics Besides.
Serang Regency is one A young calledetAnak Krakatoa appeared above (Bubeck Falguni Singh.
Mandal The of the autonomous regions within the Banten Province the sea in 1929 (Widiyanto et al.
, 2.
, and almost every year, & Chakrabarty.
Shafapour et al.
, 2.
in that the sub-districts of the West Kalimantan has a western area Tehrany directly bordering the Sunda erupts so it grows rapidly (Ningtyas et al.
, 2.
Before GISAccording and remote Thousands of houses Melawi Regency there Strait.
to Zahro the west coast of spatial Serang of the 20th same location.
Regency has a high risk for tsunamis, up to 100 m inland was an enormous volcano named Krakatau .
r Krakato.
Novian Andri Akhirianto, et al.
CHALLENGES OF TSUNAMI RISK REDUCTION
the coastline.
Related to this.
Serang Regency is dominated by a high class of tsunami hazard, covering an area of 377.
64 ha (Paramita et al.
, 2.
The conditions of the absence of early tsunami warnings, the short travel time of tsunami waves, and various other problems during the 2018 tsunami event created major challenges in mitigation and preparedness efforts in coastal areas around the Sunda Strait.
Correspondingly, this research aims to examine tsunami Disaster Risk Reduction (DRR) efforts that have been carried out after the 2018 tsunami, as well as to identify internal and external environmental factors that can be used as valuable input in developing strategies to increase resilience to tsunami hazard on the west coast area of Serang Regency.
This research is important, as it delivers some implications.
Firstly, by contributing to new knowledge regarding mitigation efforts and preparedness for tsunami.
And secondly, by providing specific information and input that can help policy makers in developing strategies to increase resilience to the tsunami.
And thirdly, by becoming a benchmarking for future research related to tsunami DRR.
justification for determining the research location sample is the villages on the west coast of Serang Regency, facing directly to the Sunda Strait.
A total of 11 villages were selected, of which 4 villages in Anyar Subdistrict (Anyar.
Tambangayam.
Cikoneng, and Bandulu Village.
, and 7 villages in Cinangka Subdistrict (Cinagka.
Kamasan.
Sindanglaya.
Karangsuraga.
Bulakan.
Pasauran, and Umbultanjung Village.
The distribution of research locations can be seen in Figure 1.
This research was conducted using a qualitative descriptive approach.
The data used is both primary and secondary data, obtained from various sources.
The primary data collections were carried out by expert interviews.
Focus Group Discussions (FGD), and field observations.
The direct interviews were conducted on 8Ae10 November 2022 with experts from stakeholders in Serang Regency (Regional Disaster Management Agency/BPBD of Banten Province and Serang Regenc.
The FGD was held at the BPBD Banten Province Office on November 9, 2022 .
ee Figure .
, aimed to verify the preparedness efforts against the tsunami, as well as to explore the roles and responsibilities of stakeholders.
Stakeholders involved in the FGD include the BPBD.
Government Social Office.
Government Public Works and Public Housing Office.
Government Tourism Office, and representatives from the subdistricts and villages of research Moreover, field observations were carried out to complete the required primary data, as well as to verify the data and information acquired from FGDs and interviews.
Methods Research was conducted on the west coast area of Serang Regency, by taking samples in 11 villages selected purposively.
According to Sugiyono .
purposive sampling is a technique for determining research samples with justification which aims to make the data obtained more representative.
The Figure 1.
Research location (Source: Research Result, 2.
Indonesian Journal of Geography.
Vol 57.
No.
Figure 2.
FGD with Serang Regency stakeholders (Source: Reseach Result, 2.
Figure 3.
Tsunami sources in the Banten Region and DKI Jakarta (Source: BMKG, 2.
Secondary data was obtained from literature studies of various documents and the results of previous scientific studies.
SWOT analysis was employed to identify the resilience of the west coast of Serang Regency to tsunami hazard.
According to (Rangkuti, 2.
SWOT analysis is defined as a logical analysis that can maximize strengths and opportunities, but simultaneously minimize the weaknesses and threats.
Subdistrict to Cinangka Subdistrict (Serang Regency, 2.
The western coastal area of Serang Regency is situated in the Sunda Strait, facing directly to the Anak Krakatau Volcano.
Topographically, the subdistrict of Anyar and Cinangka are lowlands with a gentle slope (BPS-Statistics of Serang Regency, 2023a, 2023.
The subdistrict of Cinangka has 7 coastline-bordered villages (Kamasan.
Sindanglaya.
Cinangka.
Karang Suraga.
Bulakan.
Pasauran, and Umbul Tanjun.
Hydrologically, there are 6 rivers in Serang Regency, namely the Ciujung.
Cidurian.
Cibanten.
Cipaseuran.
Cipasang and Anyar Rivers.
Moreover, there also many rivers flowing inland, which can increase the speed of tsunami waves, thus increasing the risk of tsunamis.
According to BPBD Serang Regency .
earthquakes that occurred in the Banten area and its surroundings were Result and Discussion Potential of Tsunami Hazard on the West Coast of Serang Regency The Serang Regency has an altitude of 0Ae1,778 m above sea level .
Areas with a height of 0 m asl are located on the west coast of the Sunda Strait, starting from Tirtayasa Novian Andri Akhirianto, et al.
CHALLENGES OF TSUNAMI RISK REDUCTION
influenced by the activities of Megathrust subduction, and local faults .
uch as the Ujung Kulon Fault.
Cimandiri Fault.
Palabuhan Ratu Fault, and the Semangko Faul.
The existence of a seismic gap in the south of the Sunda Strait indicates a process of stress accumulation in the earthAos crust, which can later cause strong earthquakes and trigger tsunamis.
According to Ponangsera et al .
the Sunda Strait Segment Megathrust Subduction Zone has a potential source to tsunami with high impact.
The estimated tsunami run-up in Banten from seismic activity in the Sunda Strait Segment Megathrust Subduction Zone is 5.
99 m, with a golden time of 40 minutes and 19 seconds.
According to Soloviev & Go .
there had been two earthquakes that caused tsunamis around the Sunda Strait, i.
on August 24, 1757 (Magnitude .
and December 16, 1963 (Magnitude 6.
Moreover.
BMKG has mapped tsunami sources in the Banten area based on historical tsunami events, as seen in Figure 3.
Based on the data in Figure 3, there are 6 tsunami source points around the Sunda Strait, from tectonic and non-tectonic .
Tsunamis around the Sunda Strait have occurred 7 times (BMKG, 2.
Complete historical data on tsunami events around the Sunda Strait can be seen in Table 1.
Tectonic/ Volcanic Volcanic Tectonic (Mag 7.
Table 1 shows that the volcanic-triggered tsunami around the Sunda Strait caused high fatalities, both in 1883 and 2018.
According to Soloviev & Go .
the height of the 1883 tsunami wave on the edge of the Sunda Strait was as high as 30 Meanwhile, the non-tectonic Sunda Strait tsunami in 2018 was considered a silent tsunami.
And due to the lack of early warning dissemination and minimal signs before the tsunami arrived, many people became victims (Tiwi et al.
, 2.
According to BNPB .
based on the tsunami hazard classification.
Serang Regency is one of the regions in Banten Province that has a high tsunami hazard.
The area of potential tsunami hazard in Serang Regency is 3,329 ha or 16.
5% of the total area of potential tsunami hazard in Banten Province.
Serang Regency, in terms of its level of vulnerability to tsunami, is also high.
This is due to the potential exposure of 17,404 people and potential losses of 72,592 million rupiah (BNPB.
Based on the tsunami risk analysis carried out by BNPB in 2021.
Serang Regency is included in the high risk class, that is influenced by the classes of high hazard, high vulnerability, and medium capacity.
Therefore, mitigation and preparedness efforts are highly necessary to reduce the risk of tsunami in Serang Regency.
Table 1.
History of tsunami events in the Sunda Strait Location High Tsunami source Explanation .
Lat Lon Sunda Strait No information Jawa Sea No information No.
Date
24/08/1757
18/03/1863
26/08/1883
Tectonic Volcanic Jawa Sea Sunda Strait No information Mount Kratau erupted, 36,000 people died, 297 villages suffered damage 17/03/1930 16/12/1963 Tectonic Tectonic (Mag 6.
Sunda Strait Banten No information A small tsunami occurred in Labuan 22/12/2018 Volcanic Anak Krakatau Mountain 4Ae5 431 people died, 7,200 people injured, 15 people lost, 46,646 people displaced No.
Source: BMKG .
Table 2.
Tsunami evacuation routes in Serang Regency Street name Subdistrict Umbul Tanjung Street Cinangka PasauranAeSadatani Street Cinangka Bulakan Street Cinangka KarangsuragaAeBantarwaru Street Cinangka KarangsuragaAeCinangka Street Cinangka Cinangka Street Cinangka Sindanglaya Street Cinangka KamasanAeSindanglaya Street Cinangka Kamasan Street Cinangka Bandulu Street Anyar CikonengAeTanjung Manis Street Anyar Tambangayam Street Anyar AnyarAeTanjung Manis Street Anyar MekarsariAeTanjung Manis Street Anyar Grogol IndahAeBanjarsari Street Anyar Source: Serang Regency Regional Regulation No.
5/2020
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areas in the 7 subdistrics of Serang Regency (Pulo Ampel.
Bojonegara.
Pontang.
Tirtayasa.
Tanara.
Anyar, and Cinangk.
, as specified on its RTRW document.
However, the tsunami evacuation routes that have been determined by BPBD Serang Regency in Cinangka and Anyar Subdistricts can be seen spatially in Figure 4.
According to Fisaini et al .
evacuation routes have an important role in tsunami-prone areas, especially those where there are no vertical evacuation This role is supported by the opinion of (Trindade et al.
, 2.
that establishing evacuation routes can reduce population vulnerability, make communities more resilient, and reduce the risk of disasters.
Tsunami DRR Policy in Serang Regency Post-tsunami 2018 After the 2018 tsunami, the Serang Regency Government developed a regional spatial planning strategy that had concerns about disaster-related spatial planning policies.
Based on Regional Regulation No.
5/2020 concerning amendments to Regional Regulation No.
10/2011 regarding Serang Regency Regional Spatial Planning (RTRW) for 2011-2031 there are changes related to the tsunami disaster.
Especially on the additional designated tsunami evacuation routes, from only 5 routes to 15 routes.
Complete tsunami disaster evacuation route data can be seen in Table 2.
Based on the data in Table 2, the designated tsunami evacuation routes still have not covered all tsunami-prone Figure 4.
Tsunami evacuation routes on the west coast of Serang Regency (Source: Research Result, 2.
Novian Andri Akhirianto, et al.
CHALLENGES OF TSUNAMI RISK REDUCTION
In order to integrate the spatial planning based DRR, the Serang Regency government also conducts out activities in the Sunda Strait coastal area with priority locations in Anyar Subdistrict.
The Head Section of the Utilization and Supervision for the Spatial Planning Sector of the Public Works and Public Housing Department of Serang Regency in his explanation on the FGD said that, to support the 20202024 RPJMN Major Project related to post-disaster recovery, a Detailed Spatial Planning (RDTR) for Anyar Subdistrict was prepared starting from the 2020 fiscal year.
Here, there are four disaster-prone zones in the RDTR of Anyar Subdistrict, namely: .
Development zone .
ew development priorities following applicable standard.
Conditional zone .
riority function for rural settlements with earthquake-resistant .
Limited zone .
o certain functions, for example, disaster adaptive touris.
Prohibited zone .
riority function as protected area, tsunami green belt and green open In the RDTR of Anyar Subdistrict, the main programs related to tsunami DRR are determined, such as the development of structural and non-structural mitigation infrastructure.
The development of a tsunami early warning system and tsunami retaining walls is the main structural mitigation program, while the main non-structural mitigation program consists of community development and counseling, mangrove planting, reforestation of coastal borders, as well as socialization and workshops on managing coastal border areas.
According to Daulat et al .
built-up areas from the tourism sector dominate the coastal buffer areas of Serang Regency, in the form of buildings, facilities and infrastructure for 22.
3 ha in Anyar Subdistrict and 7.
2 ha in Cinangka Subdistrict.
Thus, it is necessary to evaluate the implementation of coastal buffer zones in areas where there is a potential tsunami hazard to minimize impacts in the future.
According to Nuryanti .
RDTR plays a key role in licensing space utilization because it takes into account the carrying capacity of the environment, as the substance of RDTR has a depth of analysis with a scale of 1:5,000.
Moreover.
BPBD Serang Regency has established a policy, determining the tsunami evacuation places/shelters in Cinangka and Anyar Subdistricts.
The shelters are integrated with buildings of worship, schools and government offices.
The following Table 3 is a list of shelters designated by BPBD Serang Regency in Cinangka and Anyar Subdistricts.
Based on the data in Table 3, on the west coast of Serang Regency (Cinangka and Anyer Subdistrict.
there are no buildings specifically made for shelter.
All evacuation places designated by the BPBD Serang Regency are existing buildings that are given additional functions.
According to (BNPB, 2.
efforts to provide shelters are very strategic to anticipate tsunami disasters, especially if the time for self-rescue .
olden tim.
is very short and the coastal area is densely populated Table 3.
Tsunami evacuation place .
in Serang Regency No.
Village Umbul Tanjung Umbul Tanjung Pasauran Pasauran Bulakan Karang Suraga Sindang Laya Kamasan Bandulu Tambang Ayam Cikoneng Anyar Subdistrict Shelter name Cinangka SDN Cikokol Cinangka Masjid Kp.
Bojong Kidul Cinangka Mess Pemda Kabupaten Serang Cinangka Masjid Nur Abdillah Cinangka MTs Al Khairiyah Bulakan Cinangka Lapangan Kp.
Cipacung Cinangka Kp.
Pametung Ciparay Cinangka Pesantren Tahfidz An Nadzir Anyar Kp.
Ranca Lembang Anyar Kantor Desa Tambang Ayam Anyar Masjid Nurul Falah Kp.
Karang Jetak Anyar SMKN 1 Anyar Source: BPBD Serang Regency .
Mileage .
2,670 1,160 1,640 2,120 Figure 5.
One of the shelters on Anyar Subdistrict (Source: Research Result, 2.
Height .
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with people and buildings.
The existence of evacuation places on the west coast of Serang Regency needs to be evaluated from the aspects of capacity, evacuation routes and the community ability to reach evacuation places.
Besides, population size is also an important parameter in determining evacuation Figure 5 shows one of the shelters on Jalan Raya Anyar.
Anyar Subdistrict.
As part of the DRR tsunami.
BPBD of Serang Regency has established a policy by preparing a contingency plan document for the tsunami disaster in 2021, that aimed to respond tsunami disasters quickly, precisely, and effectively.
Besides, it can also arrange the roles and functions of each institution involved in handling the tsunami disaster (BPBD Serang Regency, 2.
According to Mowafy et al .
contingency planning is the most flexible approach and can be applied in various community conditions in order to mitigate the impact of disasters.
Responses to emergency conditions may be in effective without well-defined and implemented procedures, managerial and operational systems.
According to Alhadi et al .
with a contingency plan, stakeholders can predict the actions that will be taken when a disaster occurs, therefore they must work together to develop a comprehensive contingency plan involving all aspects.
The existence of a tsunami disaster contingency plan for Serang Regency still needs to be completed with a Disaster Risk Assessment document as part of disaster risk information services, as well as a Disaster Management Plan document as a disaster prevention and preparedness service.
This is in accordance with the mandate in Minister of Home Affairs Regulation No.
101/2018 concerning AuBasic Service Technical Standards on Minimum Service Standards for Disaster Sub-Affairs in Regency/CityAy.
Tsunami Preparedness in Serang Regency Post-Tsunami Based on Presidential Regulation No.
93/2019 concerning AuStrengthening and Development of Earthquake and Tsunami Early Warning Information SystemsAy, the Meteorology.
Climatology and Geophysics Agency (BMKG) has the authority to provide and disseminate earthquake and tsunami early warning information.
However, in the case of the tsunami in the Sunda Strait in 2018, the BMKG tsunami early warning system did not provide a warning (BMKG Earthquake and Tsunami Center, 2.
The BMKG tsunami early warning system at that time was only able to provide tsunami warnings caused by tectonic earthquakes, and was not able to process the volcanic activity of Mount Anak Krakatau, which triggered a tsunami in the Sunda Strait (Rini, 2.
In the 2018 Sunda Strait tsunami, the BMKG was only able to confirm the tsunami occurred 1.
5 hours after the actual time of the event, by checking tide gauge data in the Sunda Strait (BMKG Earthquake and Tsunami Center, 2.
Here, improving and innovating the tsunami early warning system is necessary, considering that the Sunda Strait is not the only one that has the .
Figure 6.
Siren for tsunami early warning system .
Siren building in Bulakan Village, .
Siren device in Bulakan Village, .
Siren building in Bandulu Village, .
Siren device in Bandulu Village (Source: Research Result, 2.
Novian Andri Akhirianto, et al.
CHALLENGES OF TSUNAMI RISK REDUCTION
non-tectonic tsunami potential in Indonesia.
Various volcanic activities that triggered non-tectonic tsunamis in Indonesia and caused many casualties, include the activities of Mount Gamkonora .
Mount Gamalama .
3 and 1.
Mount Awu .
Mount Ruang .
Mount Krakatau .
, and Mount Rokatenda .
(Ibrahim, 2.
order to solve this problem.
BMKG began developing a nontectonic tsunami early warning system or InaTNT, where the pilot project development and testing is in the Sunda Strait (BMKG Earthquake and Tsunami Center, 2.
Another problem related to tsunami early warning on the west coast of Serang Regency is vandalism.
This information was obtained from the Chief Executive of the BPBD Banten Province during the FGD, where vandalism occurred to the tsunami early warning siren device in Pasauran Village.
Cinangka Subdistrict.
The tsunami early warning siren in Bandulu Village.
Anyar Subdistrict, was also damaged, so it did not function.
It is necessary to increase the local communityAos knowledge of the importance of tsunami early warning sirens.
The condition of the tsunami early warning siren, which was vandalized, can be seen in Figure 6.
Moreover, road access conditions are an important factor in supporting the evacuation process.
However, on the west coast of Serang Regency, some roads used as evacuation routes were in a damaged condition.
Some evacuation routes infrastructure also needed improvement, such as the damaged bridge in Umbul Tanjung Village and dead street lights.
This condition can be dangerous, especially for the evacuation process at night.
According to Refiyanni & Silvia .
if the evacuation route is damaged it will impact the safety of the people who use it because the travel time to the evacuation site will increase.
The condition of damaged roads and bridges on the evacuation route in Umbul Tanjung Village can be seen in Figure 7.
In order to increase the community preparedness for disasters, there are intervention programs carried out by stakeholders in Serang Regency.
Disaster Resilient Village (Destan.
is one of the programs in Serang Regency which was initiated by BNPB.
Based on the Head of BNPB Regulation No.
1/2012 concerning AuGeneral Guidelines for Disaster Resilient VillagesAy.
Destana is a village that has the independent ability to adapt and face potential disaster hazards, as well as recover immediately from the adverse impacts of disasters.
As of 2021, there are already 24 Destana established in Serang Regency.
According to (Akhirianto et al.
, 2.
lack of budget and sustainability of development program implementation are the two main problems of the Destana program.
Besides, the Ministry of Social Affairs also has a Disaster Preparedness Village (KSB) program, according to Minister of Social Affairs Regulation No.
128/2011.
KSB is a community-based disaster management forum that is used as an area/place for disaster management programs.
Cinangka and Anyar Subdistricts have been designated as KSBs in Serang Regency.
One of the facilities that must be available in the KSB is a social barn as a place for storing and providing logistics and disaster needs for disaster management preparedness.
Figure 8 shows the condition of the social barns.
Tsunami DRR Challenges on the West Coast Serang Regency The resilience of the west coast area of Serang Regency to the tsunami hazard can be identified from existing internal and external environmental factors.
The internal environmental .
Figure 7.
Damage conditions on tsunami evacuation routes .
Road damage in Umbul Tanjung Village, .
Damage to bridge in Umbul Tanjung Village (Source: Research Result, 2.
Figure 8.
Social barn conditions .
Sosial barn in Cinangka Subdistrict, .
Sosial barn in Anyar Subdistrict (Source: Research Result, 2.
Indonesian Journal of Geography.
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factors can be seen from existing strengths and weaknesses, and the external environmental factors can be seen from opportunities and threats.
The tsunami DRR carried out after the 2018 tsunami can be a strength factor, as follows:
There is an intervention program to increase community Various intervention programs to increase community disaster literacy need to be done sustainably, to foster The Destana and KSB programs are examples of intervention programs that exist to increase community capacity in facing the tsunami hazard.
According to (Chen et al.
, 2.
the capacity of a region in reducing coastal disaster risk is characterized by the resources that can be mobilized during pre-disaster, emergency response and post-disaster.
There is a revision of the Serang Regency RTRW Changes on the Serang Regency RTRW based on Serang Regency Regional Regulation No.
5/2020 are expected to accommodate efforts to reduce tsunami risk, especially on the west coastal area of Serang Regency.
According to (Sagala et al.
, 2.
mainstreaming the DRR in spatial planning is important from preparation to implementation, considering that disasters will occur when there is a knowledge gap in the planning process.
The existence of the Anyar Subdistrict RDTR Spatial planning in coastal buffer areas is mandated by central and regional legislation.
The preparation of the RDTR for Anyar Subdistrict was facilitated by the Ministry of Agrarian Affairs and Spatial Planning/ National Land Agency, as a part of efforts in developing tourist areas based on disaster mitigation.
simulation activities need to be carried out periodically.
According to BNPB, .
the functions of command, control and communication between stakeholders involved in the evacuation simulation are carried out, and all available resources are synergized to overcome the emergency situations.
Besides, the external environmental factors that can affect the resilience to tsunamis on the west coast of Serang Regency are divided into opportunities and threats.
The following external environmental factors included in opportunities are as follows:
The role of universities in disaster Through the Tri Dharma of University, educational institutions have a role in tsunami DRR.
Various activities have been carried out, including analysis of the disaster curriculum for basic education to higher education.
Kuliah Kerja Mahasiswa (KKM) on disaster thematics, disaster education for the community, and disaster Availability of village funds for disaster mitigation and preparedness programs Based on Government Regulation No.
60/2014 jo.
Government Regulation No 8/2016, village funds are used to fund the government administration, implementation of community development, and community In accordance with the Regulation of the Minister of Villages.
Development of Disadvantaged Regions and Transmigration No.
7/2021, there are three main points regarding the priority use of village funds in 2022, one of which is to mitigate and handle natural and non-natural disasters according to village authority.
There is a pentahelix collaboration in tsunami PRB Pentahelix elements in Serang Regency played a role in the tsunami DRR, such as government elements through various Regional Apparatus Organizations (OPD), academics from universities, elements of the business .
epresented by hotel and restaurant owner.
, mass media, and elements of society.
According to Arfani .
through pentahelix collaboration, the community gains knowledge of disasters and efforts to reduce disaster risks, so that the community has preventive knowledge on the potential disasters.
Moreover, the internal environmental factors included in the weaknesses based on research results are as follows:
Limitations of tsunami early warning device The western coastal area of Serang Regency still needs to improve the installed tsunami early warning sirens.
The availability of tsunami early warning device is limited, and their condition is also damaged and subjected to The existence of a tsunami early warning system is highly needed by the community, local government and related parties as a warning sign for quick evacuation, considering that not all tsunami phenomena have the same natural signs.
Limited tsunami evacuation facilities Tsunami evacuation facilities such as evacuation routes, temporary evacuation places, and evacuation route signs have been carried out by the Serang Regency BPBD.
However, there is still a need to repair the roads and bridges, evaluate the capacity and strength of shelter structures, as well as socialize the tsunami evacuation routes to the community.
Apart from that, shelters which function as evacuation places for the community are currently not available on the west coast area of Serang Regency.
There is no continuous tsunami evacuation simulation Tsunami evacuation simulation activities can increase the communityAos capacity to face the tsunami, as well as may test and evaluate the evacuation procedures that have been established in the contingency plan document, as was done by the Serang Regency BPBD on June 22, 2022 in Anyar Subdistrict.
However, tsunami evacuation Finally, the external environmental factors included in the threats based on the research results are:
Potential hazard of tectonic and non-tectonic tsunamis Based on various previous research, there are a tsunami hazards on the west coast area of Serang Regency, sourced from the tectonic plate of Sunda Megathrust for tectonic, as well as from the non-tectonic activity of the Anak Krakatau Volcano.
Potential for increasing population density in coastal Population density in Cinangka District 546 per km2 in 2020 to 562 per km2 in 2022.
And the population density of Anyar District increased from 1,034 per km2 in 2020 to 1,067 per km2 in 2022 (BPS-Statistics of Serang Regency, 2021, 2023.
Population density is an important variable that can provide an overview of the population at risk and population concentration in disaster-prone areas.
Novian Andri Akhirianto, et al.
CHALLENGES OF TSUNAMI RISK REDUCTION
The higher the level of population density, the higher the vulnerability to the risk of tsunami.
Potential to increase the number of tourist visits After the 2018 tsunami disaster, beach tourism visitors in Serang Regency tended to increase, from 347,807 visitors in 2019 to 350,821 visitors in 2022.
According to Prihartanto et al .
the more tourist visitors, the greater the potential for people to be affected by a tsunami.
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Ay Conclusion Some progress in tsunami DRR has been achieved on the west coast of Serang Regency after the 2018 tsunami.
However, there are still challenges and gaps that need to be addressed to increase resilience to tsunamis.
Firstly, the existence of a robust tsunami early warning system, which can detect seismic and non-seismic tsunamis, is urgently needed.
Considering that the tsunami hazard does not only come from tectonic earthquakes, but also from non-tectonic ones .
he activity of the Anak Krakatau Volcan.
Secondly, the existing tsunami early warning device and evacuation infrastructures needed to be improved and protected from vandalism.
So that the hazard of tsunamis on the west coast of Serang Regency can be anticipated with mitigation and increased preparedness.
Moreover, spatial planning in Serang Regency is gradually being adapted to be more sensitive to disasters in order to reduce disaster risks.
The policy for structuring and managing coastal areas based on disaster mitigation has been implemented since 2020, through the revision of the RTRW and the preparation of the RDTR for Anyar Subdistrict.
requires good socialization to the community, followed by appropriate programs and budget allocation.
Apart from that, implementation needs to be monitored and accompanied by law enforcement to minimize the impact of tsunamis that could occur in the future.
Furthermore, ther is an urgent need for innovative approaches that can reduce tsunami risks, one of which is by educating the public about the risks and signs of tsunamis as well as how to respond and act early.
And formulating a strategy to increase resilience to tsunamis can be done by utilizing 3 strengths and 3 opportunities, as well as minimizing 3 weaknesses and 3 existing threats.
Apart from that, synergy between stakeholders and the sustainability of existing tsunami DRR programs are needed, because this will also determine the success of collaborative work to create a tsunami-resilient west coast of Serang Regency.
Acknowledgement The authors would like to express gratitude to BRIN for fully supporting this research.
References