Suchergebnisse

Abstract. The primary background for the present study was a project to assist the authorities in Thailand with development of plans for how to deal with the future tsunami risk in both short and long term perspectives, in the wake of the devastating 26 December 2004 Sumatra-Andaman earthquake and tsunami. The study is focussed on defining and analyzing a number of possible future earthquake scenarios (magnitudes 8.5, 8.0 and 7.5) with associated return periods, each one accompanied by specific tsunami modelling. Along the most affected part of the western coast of Thailand, the 2004 tsunami wave caused a maximum water level ranging from 5 to 15 m above mean sea level. These levels and their spatial distributions have been confirmed by detailed numerical simulations. The applied earthquake source is developed based on available seismological and geodetic inversions, and the simulation using the source as initial condition agree well with sea level records and run-up observations. A conclusion from the study is that another megathrust earthquake generating a tsunami affecting the coastline of western Thailand is not likely to occur again for several hundred years. This is in part based on the assumption that the Southern Andaman Microplate Boundary near the Simeulue Islands constitutes a geologic barrier that will prohibit significant rupture across it, and in part on the decreasing subduction rates north of the Banda Ache region. It is also concluded that the largest credible earthquake to be prepared for along the part of the Sunda-Andaman arc that could affect Thailand, is within the next 50–100 years an earthquake of magnitude 8.5, which is expected to occur with more spatial and temporal irregularity than the megathrust events. Numerical simulations have shown such earthquakes to cause tsunamis with maximum water levels up to 1.5–2.0 m along the western coast of Thailand, possibly 2.5–3.0 m on a high tide. However, in a longer time perspective (say more than 50–100 years) the potentials for earthquakes of similar magnitude and consequences as the 2004 event will become gradually larger and eventually posing an unacceptable societal risk. These conclusions apply only to Thailand, since the effects of an M 8.5 earthquake in the same region could be worse for north-western Sumatra, the Andaman and Nicobar Islands, maybe even for Sri Lanka and parts of the Indian coastline. Moreover, further south along the Sunda arc the potentials for large ruptures are now much higher than for the region that ruptured on 26 December 2004.

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB). The RENEB project started in January 2012 involving cooperation of 23 organisations from 16 European countries. The purpose of RENEB is to increase the biodosimetry capacities in case of large-scale radiological emergency scenarios. The progress of the project since its inception is presented, comprising the consolidation process of the network with its operational platform, intercomparison exercises, training activities, proceedings in quality assurance and horizon scanning for new methods and partners. Additionally, the benefit of the network for the radiation research community as a whole is addressed.