Coastal and settlement typologies-based tsunami modeling along the northern Sumatra seismic gap zone for disaster risk reduction action plans (original) (raw)
Abstract
Since after the 2004 Indian Ocean tsunami, multiple efforts have been carried out to investigate the occurrence potential of tsunami-generating earthquakes. One of the studies concluded that large earthquakes are expected to occur along the seismic gap zone in the west coast of Sumatra and thus have the potential to generate tsunamis. The objectives of the research are to (1) investigate the existence of the seismic gap zone and to calculate the potential energy of expected earthquakes along the zone; (2) develop a tsunami model based on the relation between tsunami amplitude, arrival time, and coastal and settlement typologies; and (3) suggest tsunami mitigation action plans for surrounding areas in order to reduce the risk of disaster. The earthquake distribution in Aceh indicates the presence of a seismic gap zone in the west coast of Aceh, indicated by the decrease in seismic activities within the area since 2008. The potential energy is equivalent to an Mw 8.7 earthquake. The earthquake has the potential to generate a tsunami with a maximum amplitude of 20 m in the west coast of Aceh. An analytic hierarchy process (AHP) analysis was applied to determine the hazard and vulnerability levels. Having the information of hazards and vulnerability, we derived the priority level of the study area and suggested the tsunami mitigation action that needs to be applied to the area. The results indicate that the AHP method gave stable results in the determination of the vulnerability, hazard, and priority levels and thus can be used for other regions of similar coastal and settlement typologies.
The results also show that Banda Aceh, Calang, and Meulaboh cities are zones of priority level 1, where all components of tsunami action plans should be implemented, comprising (1) the provision of an early warning system and related information; (2) the construction of evacuation routes and buildings; (3) the improvement of knowledge of disaster risk; and (4) the strengthening of awareness and preparedness. All action plans should be applied for Blang Pidie, as the city is included in an area of priority level 2. For the areas with priority level 3, including Tapak Tuan, and Singkil, the government should improve knowledge of disaster risk and strengthen community awareness and preparedness.
Introduction
After the 2004 Indian Ocean tsunami, efforts to reduce the risk of tsunami disasters in Sumatra have been carried out in various forms (e.g. Ref. [[1], [2], [3], [4]]). One of them is the establishment of a tsunami early warning system. The system consists of four integrated elements: monitoring and warning, information dissemination, tsunami disaster risk education, and community preparedness and awareness of disaster risk [4]. Tsunami modeling has been carried out to determine the estimated arrival times and amplitudes along coastal areas in Indonesia [5,6]. However, comprehensive research on tsunamis covering the seismic gaps, potential energy, and efforts to reduce the risk of tsunami disasters still needs to be conducted [[7], [8], [9]]. Based on the tectonic setting, the tsunami potential in Sumatra is influenced by two main fault systems: the subduction zone and the investigator fracture zone [[10], [11], [12]] (Fig. 1). The main potential source of tsunamis in this region is the subduction zones off the west coast of Sumatra, since almost 90% of the tsunamis were caused by earthquake activities along the subduction zone [2,13].
Aydan (2008) [14] stated that a zone of potential tsunamis generated by earthquakes exists in the west coast zone of Sumatra. This zone is known as a seismic gap zone, that is, an area that has an active history of earthquakes in the past but is currently less active [14,15]. The decrease in earthquake activity is associated with an energy accumulation process, so that such a zone has the potential of generating earthquakes with a magnitude larger than Mw 8 in the future [14,16]. Therefore, the Indonesian National Disaster Management Agency in 2015 [17] stated that the coastal region of Sumatra is among the three main prioritized areas in the efforts to reduce the risk of tsunami disasters.
After the 2004 Indian Ocean tsunami, Strunz et al. [4] examined the tsunami potential in Indonesia, and the results were then used as a database of the tsunami parameters in the Indonesian tsunami early warning system. Furthermore, Pribadi et al. [2] classified tsunami characteristics based on the waveform data of recorded earthquakes. Research on tsunamis has also been carried out to develop regional tsunami mitigation action plans based on coastal typology and population [3,19].
Earthquakes as main triggers of tsunamis generally tend to reoccur over a certain period. In other words, earthquake-caused tsunamis may also reoccur in certain time periods. Potential seismic zones can be identified by examining the history of earthquake activities [12,20]. The pattern of earthquake distribution provides important information related to the processes of earthquake events [16]. The distribution pattern of tectonic earthquake activity is defined as an earthquake cycle, while a cycle itself is defined as the stress accumulation process until the stress reaches a critical condition (critical stress) and returns to the initial condition (initial stress). This study aimed to update the information on the existence of seismic gap zones off the west coast of Sumatra and the potential earthquake energy in those zones as a database to develop tsunami models. The tsunami models were developed based on an analysis of the relationship between estimated tsunami amplitude and arrival times and coastal and settlement typologies. The tsunami modeling results were then used to determine the hazard, vulnerability, and priority levels, which determine the tsunami mitigation action plans to be applied in an area. This concept can be applied to all tsunami-prone areas [3,6].
Section snippets
Data and methods
The 1976 to 2008 earthquake data were obtained from the United States Geology Survey (USGS), while the 2009 to 2018 data were obtained from the Meteorology, Climatology, and Geophysics Agency (BMKG). For tsunami modeling, we used bathymetry data at 30 arc-seconds resolution from GEBCO [21] and the digital elevation model of the Shuttle Radar Topography Mission with 1 arc-second resolution (USGS) (www.earthexplorer.usgs.gov) [22]. Complementary data such as the Sumatran administrative boundary
Seismic gap zone
To determine the seismic gap zone, we mapped the locations of subduction earthquakes of 1976–2018 in Aceh with magnitudes larger than M 2.0, provided by USGS and BMKG. In the last seven years, 6923 earthquakes have occurred in Sumatra, which means around 900 seismic events are generated every year. Although Sumatra is one of the most seismically active regions, as indicated by the earthquake occurrences, it contains a seismic gap zone, indicated by the yellow circles in Fig. 4, whose number of
Conclusions
Earthquake distribution in the period of 1976–2018 in Sumatra shows a variation in seismic activity; at least, four warnings of tsunamis associated with large earthquakes were issued. A large earthquake has the potential to occur along the seismic gap zone, which is characterized by less frequent earthquake occurrences. The accumulated potential energy is equivalent to an Mw 8.7 earthquake that can cause a fault rupture of 282 km length and 141 km width. The thrust faulting earthquake is
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
We thank the Meteorology, Climatology and Geophysics Agency (BMKG) for providing the arrival time data of earthquake. The research was funded by Ministry of Research and Higher Education, Indonesia, under the scheme of Applied Research.
References (40)
Int. J. Disaster Risk Reduct.
(Aug. 2020)
- A.K. Kuncoro et al.
Tsunamigenic potential due to frontal rupturing in the Sumatra locked zone
Earth Planet Sci. Lett.
(2015)
- O. Bellier
Paleoseismicity and seismic hazard along the great sumatran fault (Indonesia)
J. Geodyn.
(1997)
- P. Nuannin et al.
Spatial and temporal characteristics of aftershocks of the December 26, 2004 and March 28, 2005 earthquakes off NW Sumatra
J. Asian Earth Sci.
(2012)
- U. Muksin et al.
Detailed fault structure of the Tarutung Pull-Apart Basin in Sumatra, Indonesia, derived from local earthquake data
J. Asian Earth Sci.
(2014)
- U. Muksin
AcehSeis project provides insights into the detailed seismicity distribution and relation to fault structures in Central Aceh, Northern Sumatra
J. Asian Earth Sci.
(2019)
- P. Nuannin et al.
Spatial and temporal characteristics of aftershocks of the December 26, 2004 and March 28, 2005 earthquakes off NW Sumatra
J. Asian Earth Sci.
(2012)
- Y. Xu et al.
Earthquake prediction based on community division
Phys. A Stat. Mech. its Appl.
(2018)
- N. Puspito et al.
Tsunami sources in the sumatra region, Indonesia and Simulation of the 26 December 2004 Aceh tsunami
ISET J. Earthq. Technol.
(2005)
- S. Pribadi et al.
Characteristics of earthquake-generated earthquake tsunamis in Indonesia nesia based on source parameter analysis
J. Math. Fund. Sci.
(2013)
- D. Mardiatno et al.
Review on tsunami risk reduction in Indonesia based on coastal and settlement typology
Indones. J. Geogr.
(2017)
- G. Strunz
Tsunami risk assessment in Indonesia
Nat. Hazards Earth Syst. Sci.
(2011)
- N. Horspool
A probabilistic tsunami hazard assessment for Indonesia
Nat. Hazards Earth Syst. Sci.
(2014)
- B.W.R. Mccann et al.
Seismic gaps and plate tectonics: seismic potential for major boundaries
Pure Appl. Geophys.
(1979)
- H.A. Haridhi et al.
A study of large earthquake sequences in the Sumatra subduction zone and its possible implications
Terr. Atmos. Ocean Sci.
(Dec. 2018)
- K. Wiseman et al.
Stress and seismicity changes on the sunda megathrust preceding the 2007 Mw 8.4 earthquake
Bull. Seismol. Soc. Am.
(2011)
- H.T.H. Verstappen
Indonesian landforms and plate tectonics
Int. J. Geol.
(2010)
- A.J. Barber et al.
Suma: Geology, Resources, and Tectonic Evolution
(2001)
- O. Aydan
Seismic and tsunami hazard potentials in Indonesia with a special emphasis on sumatra island
Journal of The School of Marine Science and Technology
(2008)
- L. Hamzah et al.
Tsunami catalog and zones in Indonesia
J. Nat. Disaster Sci.
(2000)
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2023, Progress in Disaster Science
In numerical simulations, we simulate several tsunami conditions, which are generated by earthquakes with varying magnitudes in the range of Mw 8.7–9.3. The lowest magnitude (Mw 8.7) is based on the probability of earthquake energy being reached since the 2004 Indian Ocean earthquake (i.e. almost 20 years) [8], with the maximum magnitude (according to the seismic moment) reaching 1 × 1030 dyn cm or equivalent to the moment magnitude (Mw) 9.3 [19,20]. The resulting tsunami hazard zone is an inundation zone that previously covered the potential tsunami height on the coastline [9,21,22].
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