scholarly journals Tsunami simulation for disaster mitigation based on earthquake scenarios in the Molucca subduction zone (case study of the Molucca Sea earthquake on July 7, 2019)

2021 ◽  
Author(s):  
Telly Kurniawan ◽  
Rahmat Setyo Yuliatmoko ◽  
Bambang Sunardi ◽  
Angga Setiyo Prayogo ◽  
Muzli Muzli ◽  
...  
2020 ◽  
Author(s):  
Dimitra Salmanidou ◽  
Mohammad Heidarzadeh ◽  
Serge Guillas

<p>Historical earthquakes in the Java subduction zone have given genesis to tsunami affecting the southwest coasts of the island of Java, in Indonesia. The most recent earthquake on the 17<sup>th</sup> of July 2006, has given rise to a tsunami that killed more than 600 people. The tsunami was difficult to escape due to the small amount of ground shaking, which could have acted as an early warning, and due to the epicentre being very close to the shorelines, giving insufficient time for response. Historical data and scientific studies give little evidence for mega-thrust events in the Java trench, however such possibilities are not excluded and could have a devastating impact in the region. This work aims to assess the tsunami hazard occurring from a range of earthquake scenarios in the subduction zone. Taking as a benchmark the 2006 event, we initially validate our modelling approach against the wave observations recorded at three tide gauges. We then expand our work to account for future earthquake scenarios and their tsunamigenic consequences in the southern coasts of Java island. Bathymetry displacement is computed using the Okada elastic dislocation model. The nonlinear shallow water equation solver JAGURS is employed for the modelling of wave propagation. Our objective is to quantify the uncertainty of such events by using statistical surrogates: fast stochastic approximations of the model that can explore the likelihood of thousands of tsunami scenarios in a few moments of time. Gaussian process emulators are utilised to predict maximum wave amplification occurring from varying parameter distributions such as the moment magnitude of an earthquake. The resulting tsunami hazard footprints can be used in conjunction with existing socio-demographic information to assess tsunami risk in vulnerable areas. The end-data can eventually be used to inform policy making for better disaster mitigation planning.</p>


Author(s):  
S. Enferadi ◽  
Z. H. Shomali ◽  
A. Niksejel

AbstractIn this study, we examine the scientific feasibility of an Earthquake Early Warning System in Tehran, Iran, by the integration of the Tehran Disaster Mitigation and Management Organization (TDMMO) accelerometric network and the PRobabilistic and Evolutionary early warning SysTem (PRESTo). To evaluate the performance of the TDMMO-PRESTo system in providing the reliable estimations of earthquake parameters and the available lead-times for The Metropolis of Tehran, two different approaches were analyzed in this work. The first approach was assessed by applying the PRESTo algorithms on waveforms from 11 moderate instrumental earthquakes that occurred in the vicinity of Tehran during the period 2009–2020. Moreover, we conducted a simulation analysis using synthetic waveforms of 10 large historical earthquakes that occurred in the vicinity of Tehran. We demonstrated that the six worst-case earthquake scenarios can be considered for The Metropolis of Tehran, which are mostly related to the historical and instrumental events that occurred in the southern, eastern, and western parts of Tehran. Our results indicate that the TDMMO-PRESTo system could provide reliable and sufficient lead-times of about 1 to 15s and maximum lead-times of about 20s for civil protection purposes in The Metropolis of Tehran.


2019 ◽  
Vol 34 (s1) ◽  
pp. s8-s8 ◽  
Author(s):  
Dudley McArdle ◽  
Caroline Spencer ◽  
Frank Archer

Introduction:Despite the influential Hyogo and Sendai Frameworks, risk remains poorly understood in the emergency preparedness sector. Hazard assessment and risk management are usually considered before events. An alternative view considers risk as a cascade of potential consequences throughout an event. The 2014 fire in the Victorian rural community of Morwell included a three-phased event: a small bush fire, from which embers ignited a persistent fire in a disused open cut brown coal mine fire. The consequent air pollution precipitated a public health emergency in the nearby community of 15,000 people.Aim:To examine this event as a case study to investigate concordance with accepted definitions and key elements of a cascading event.Methods:Selected literature informed a risk cascade definition and model as a framework to examine the key post-event public inquiries available in the public domain.Results:Informed by a Conceptual Framework for a Hazard Evolving into a Disaster (Birnbaum et al., 2015), Wong and colleagues promote a Core Structure of a Comprehensive Framework for Disaster Evaluation Typologies (Wong, 2017). This Core Structure provided an adequate model to examine the sequence of events in the Morwell event. Definitions of cascading effects is more complex (Zuccaro et al., 2018). Our analysis of the Morwell event used the authoritative definition of cascading disasters published by Pescaroli and Alexander (2015). Using this definition, the Morwell event increased in progression over time and generated unexpected secondary events of strong impact. The secondary events could be distinguished from the original source of disaster, and demonstrated failures of physical structures as well as inadequacy of disaster mitigation strategies, while highlighting unresolved vulnerabilities in human society.Discussion:The Morwell coal mine fire of 2014 reflects the key criteria of a cascading disaster and provides understandings to mitigate the consequences of similar events in the future.


2019 ◽  
Vol 9 (2) ◽  
pp. 152
Author(s):  
Rahmat Setyo Yuliatmoko ◽  
Telly Kurniawan

The amount of stress released by an earthquake can be calculated with a stress drop, the stress ratio before and after an earthquake where the stress accumulated in a fault or a subduction zone is immediately released during an earthquake. The purpose of this research is to calculate the amount of stress drop in faults and subduction in Maluku and Halmahera and their variations and relate them to the geological conditions in the area so that the tectonic characteristics in the area can be identified. This research employed mathematical analysis and the Nelder Mead Simplex nonlinear inversion methods. The results show that Maluku and Halmahera are the area with complex tectonic conditions and large earthquake impacts. The Maluku sea earthquake generated a stress drop of 0.81 MPa with a reverse fault mechanism in the zone of subduction, while for the Halmahera earthquake the stress drop value was 52.72 MPa, a typical strike-slip mechanism in the fault zone. It can be concluded that there is a difference in the stress drop between the subduction and fault zones; the stress drop in the fault was greater than that in the subduction zone due to different rock structure and faulting mechanisms as well as differences in the move slip rate that plays a role in the process of holding out the stress on a rock. This information is very important to know the amount of pressure released from the earthquake which has a very large impact as part of disaster mitigation measures.


2008 ◽  
Vol 96 (3-4) ◽  
pp. 126-140 ◽  
Author(s):  
E. Alparslan ◽  
F. Ince ◽  
B. Erkan ◽  
C. Aydöner ◽  
H. Özen ◽  
...  

Author(s):  
Takako Hashimoto ◽  
David Lawrence Shepard ◽  
Tetsuji Kuboyama ◽  
Kilho Shin ◽  
Ryota Kobayashi ◽  
...  

Abstract During a disaster, social media can be both a source of help and of danger: Social media has a potential to diffuse rumors, and officials involved in disaster mitigation must react quickly to the spread of rumor on social media. In this paper, we investigate how topic diversity (i.e., homogeneity of opinions in a topic) depends on the truthfulness of a topic (whether it is a rumor or a non-rumor) and how the topic diversity changes in time after a disaster. To do so, we develop a method for quantifying the topic diversity of the tweet data based on text content. The proposed method is based on clustering a tweet graph using Data polishing that automatically determines the number of subtopics. We perform a case study of tweets posted after the East Japan Great Earthquake on March 11, 2011. We find that rumor topics exhibit more homogeneity of opinions in a topic during diffusion than non-rumor topics. Furthermore, we evaluate the performance of our method and demonstrate its improvement on the runtime for data processing over existing methods.


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