Field Survey of Northern Sumatra and Banda Aceh, Indonesia after the Tsunami and Earthquake of 26 December 2004

Abstract

On Sunday, 26 December 2004, at 00:58 UTC (07:58 local at the epicenter), a great earthquake occurred 250 km south-west of Banda Aceh in northern Sumatra, Indonesia. With a moment magnitude of 9.0 or possibly greater (Stein and Okal, 2005), it was one of the largest instrumentally recorded earthquakes in history. The earthquake generated a large tsunami that caused extreme inundation and destruction along the northern and western coasts of Sumatra, as seen in the cities of Banda Aceh and Meulaboh. Within hours the tsunami devastated the distant shores of Thailand to the east as well as those of Sri Lanka, India, and the Maldives to the west. The tsunami also caused deaths and destruction in Somalia and other nations of east Africa and was recorded on tidal stations throughout the oceans of the world. Figure 1. Location map showing survey sites. A representative value for the maximum wave height or run-up at each location is given. The rapid response of an International Tsunami Survey Team (ITST) to the Banda Aceh, Sumatra region after the 26 December 2004 earthquake and tsunami led to the recovery of important data on the characteristics of the tsunami inundation. These data are used in conjunction with satellite imagery obtained before and shortly after the earthquake to describe the effects of the tsunami and earthquake in terms of run-up height, inundation distance, flow depth, levels of structural damage, shoreline erosion, and earthquake-related subsidence. Field data collected in Banda Aceh and nearby areas include profiles to determine run-up heights, GPS-located photographs of flow depth marks, and traces indicating flow direction. Additional information on wave arrival and behavior was collected through interviews with witnesses and survivors and from video taken during the tsunami attack. As a member of the International Tsunami Survey Team (ITST), I entered the Aceh region …