DATA BASE DEVELOPMENT OF ETA (ESTIMATED TIME OF ARRIVAL) FOR TSUNAMI DISASTER MITIGATION AT SOUTHWESTERN CITIES OF ACEH, INDONESIA

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1 6 th South China Sea Tsunami Workshop Nanyang Technology University, Singapore, 6-8 November 2013 DATA BASE DEVELOPMENT OF ETA (ESTIMATED TIME OF ARRIVAL) FOR TSUNAMI DISASTER MITIGATION AT SOUTHWESTERN CITIES OF ACEH, INDONESIA Teuku M Rasyif 1, Syamsidik 1, Shigeru KATO 2, Takumi OKABE 2 1 Tsunami and Disaster Mitigation Research Center (TDMRC) Banda Aceh , INDONESIA teukumrasyif@gmail.com, syamsidik@tdmrc.org 2 Department of Architectural and Civil Engineering Toyohashi University of Technology Toyohashi , JAPAN s-kato@ace.tut.ac.jp, okabe@jughead.ace.tut.ac.jp

2 Background Occurance big earthquakes and tsunami December 26, 2004 with a This event was caused chaos in magnitude Mw > 9.0 the southwestern coast area such March 28, 2005 with magnitude as mass panic and traffic density. Mw = 8.6 That can lead to congestion, April 11, 2012 by two of the largest accidents, and the ineffectiveness strike-slip earthquakes with of the tsunami evacuation. magnitude (Mw = 8.6 and 8.2) ever This condition resulted from recorded (Duputel et al., 2012) ignorance of community and government in education and enhance preparedness for tsunami disaster.

3 Problems that are expected to be resolved from this research are as follows: 1. What and how the local community and local government preparedness toward tsunami can be enhanced? 2. What is the shortest tsunami wave estimated time of arrival for the Aceh's southwestern cities that should be included into evacuation procedure? 3. How can we integrate the ETA information into tsunami mitigation? Research Objectives The objective of this research is to improve preparedness of community and local government toward tsunami hazard by developing the data base of tsunami ETA (Estimated Time of Arrival). Benefit of research The data will be used as education and basic information for community and local government to predict tsunami arrival time, to arrange an evacuation outline, and to enhance disaster mitigation in the Southwestern of Aceh

4 Study Area The areas of simulation will be used are Meulaboh, Lageun the capital of the Aceh Jaya Regency, Calang, and Tapaktuan located along the southwestern coast of Aceh Province. Calang and Meulaboh are the worst area effected cities by the tsunami impacts in That was indicated by the number of victims, destroyed buildings houses, and roads. This condition was occurred due to a flat topography of the cities, and position of the cities and the main road connecting between Banda Aceh and Meulaboh. Tapaktuan is the unaffected area by tsunami. However, due to the indicated seismic gap explained in the previous section, Tapaktuan is a future anticipated tsunami area.

5 Earthquake Scenarios Past Earthquake The number of simulation scenarios used are based on magnitude of earthquake larger Mw = 7 that occur around Sumatera subduction zone based on Global CMT database with interval Future Earthquake Based on previous study Schlurmann et al, (2010) have indicated a seismic gap near Padang (capital city of West Sumatra) which is still locked with return period at about 200 years and it can be a trigger to a tsunami earthquake. The seismic source has been estimated by observing continuous Global Positioning Satellite (cgps) and carbon dating of coral growth. The seismic source parameters obtained from Kongko (2011)..

6 Grid Setup Layer Extent of grid (geographic, WGS84) No Longitude Latitude Grid Spacing 1 min 1851 m 0.2 min m m 125 m Number of grids Coordinate System Type of SWE 1731 x 1693 Spherical Linear 1918 x 1879 Spherical Linear 2441 x 1687 Spherical NonLinear Grid 1 is used GEBCO data with resolution 0.5 min. Spacing grid used for Layer 1 was 1 min. Bathymetry and topography data for Layer 2 obtained by interpolating GEBCO data with resolution data 0.5 min to 0.2 min. At layer 3, the topographic data obtained by interpolating GEBCO data into grid with resolution min ( 125 m). While the bathymetric obtained by interpolating GEBCO data and then updating it by digitized an available nautical chart with scale (1: ).

7 The ETA (ESTIMATED TIME OF ARRIVAL) No. Name of City Padang 2007 (8.5) 2007(2) Distance ETA Distance ETA Distance ETA Distance ETA Distance ETA Distance ETA Distance ETA Distance ETA (km) (minutes) (km) (minutes) (km) (minutes) (km) (minutes) (km) (minutes) (km) (minutes) (km) (minutes) (km) (minutes) 1 Lageun Calang Meulaboh Tapaktuan The ETA as the result are obtained by put observation points at selected locations with the bathymetry depth about 10 m and tsunami height reach 0.5 m. That results show the minimum escape window time for people in coastal area based on Indian Ocean tsunami in 2004 are about 25, 29, 35, and 37 minutes at Lageun, Calang, Meulaboh, and Tapaktuan A moderate escape window time is about 62, 72, 78, 46 based on tsunami in The ETA for around outside subduction zone can be used the data based on tsunami in 2012 with interval time 81, 80, and 74 minutes at Lageun, Calang, and Meulaboh.

8 Considering the ETA data the big earthquakes on January and April 2012 are generate tsunami with arrival time about 90 and 80 minutes. Seawater receded and rise have been founded in several city such as Meulaboh and Banda Aceh thought not caused big disaster. Geophysical and Meteorological Agency (BMKG) have been posted tsunami warning on their website on January and April In Banda Aceh (main city of Aceh) lack evacuation is occur due the local community is unaccepted the warning information and caused mass panic and traffic jam due to ineffective evacuation.

9 Question from local community How if big earthquake occur around with magnitude as same as with the big earthquake in 2004, is that can generate tsunami?? Maximum tsunami height

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11 EVACUATION PROCEDURE Local Community The database can be used as education by know escape window of tsunami arrival. Hence local community will be always prepare and aware due to an earthquake s occurrence. - Local community can use about 5-10 minutes to find information and notice nature's tsunami warning signs. Relationship between death toll and time to start refuge (Sugimoto et al. 2002)

12 Local government The database can be used as enhance disaster mitigation in the southwestern coast in Aceh Province. -Conduct tsunami evacuation drill to educate local community then an uneffective evacuation on the 2012 is not happen again. - Spatial planning around coastal area by relocate local community's house. The regulations have been issued by the government to enhanced mitigation in Aceh after tsunami in 2004 to move further about 500 m from coastal area. 50 m (Syamsidik and Istiyanto 2012)

13 CONCLUSION Spacial planning, arrange an evacuation outline, tsunami evacuation drill, information to predict tsunami arrival time Effective ETA can be use as enhanced mitigation for southwestern of Aceh based on simulation is Indian Ocean tsunami in 2004 with evacuation time about 30 minutes The database of ETA as basic information can be education for local community and local government to enhanced tsunami mitigation

14 Nun. By the pen and what they inscribe THANK YOU VERY MUCH