28 th March 2005 magnitude 8.7 earthquake Northern Sumatra, Indonesia

Transcription

1 29 th March 2005 GAPResponse 28 th March 2005 magnitude 8.7 earthquake Northern Sumatra, Indonesia Russell Blong T: F: E: russell.blong@benfieldgroup.com Ben Miliauskas T: F: E: ben.miliauskas@benfieldgroup.com Brad Weir T: F: E: brad.weir@benfieldgroup.com Benfield Group Limited All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, whether electronic or mechanical, without the written permission of the copyright holder. This document is intended exclusively for the use of the individual, directors and employees of the organisation to which it was originally provided, and is not to be made available to third parties without the specific agreement of Benfield Group. Benfield Group has used due care in the preparation of this document. Our information has been obtained from sources we consider to be reliable but its accuracy or completeness is not guaranteed. Benfield Group shall owe no liability whatsoever to any person for any loss or damage caused by or resulting from any error in such information.

2 Contents Overview of Event 3 Summary of Observed Impacts 5 Insurance Losses 6

3 Overview of Event A large earthquake of magnitude 8.7 was recorded off the northern coast of Sumatra at 11:09pm local time in Indonesia (16:09 UTC) on Monday, 28 th March. The earthquake epicentre was situated 34.7km SW of Alban (Banyak Islands), 205 km west northwest of Sibolga, Sumatra, or about 1,410 km northwest of Jakarta, Java in Indonesia. The earthquake has been followed by a number of aftershocks with two of these registering a magnitude greater than 6.0. Initial statements claim the earthquake was an aftershock from the 26 th December magnitude 9.3 earthquake which occurred about 160 km to the northwest. The 28 th March earthquake occurred on the interface between the Australia and Sunda plates and was caused by the release of stresses as the Australia plate subducts beneath Sumatra. The location of these two significant earthquakes is shown in Figure 1. Figure 1 Location of the 8.7 earthquake in relation to the 26 th December earthquake (source: USGS) Page 3 - GAPResponse

4 The earthquake was widely felt across Sumatra and the Nicobar Islands in India, approximately 700km to the northwest. Shaking was reported in Singapore and Malaysia and in Bangkok in Thailand. Tsunami warnings were issued by a number of regions including Thailand, Indonesia and Nicobar Islands, India and as far away as the islands of Mauritius and Madagascar more than 4,000km from the epicentre. However, these warnings have since been lifted. The majority of reported casualties and damage stem from the surrounding islands of Nias and Simeulue, both located within 90km of the epicentre. Initial estimates from the island of Nias indicate that over 70% of the buildings in the main town of Gunungsitoli, have been destroyed. It has also been reported that the island of Simeulue has also suffered damage, possibly by a three metre high tsunami generated by the earthquake. Initial modelling by the National Tidal Centre and the Bureau of Meteorology indicates that tsunami wave heights expected from this event are not as significant as those experienced from the 26 th December tsunami. Modelled maximum tsunami height around the northern Indian Ocean region shown in Figure 2 are in the order of 0.5m. This correlates well with observations on the Cocos Islands where a height of about 20cm was observed. Figure 2 Provisional model results for the 28 th March tsunami from the National Tidal Centre Page 4 - GAPResponse

5 Summary of Observed Impacts Observations the earthquake was widely felt in Sumatera and the Nicobar Islands in India with shaking reported in Singapore and Malaysia and in Bangkok in Thailand there were no reports of damage or casualties in Banda Aceh, where the quake lasted two minutes and briefly cut electricity tsunami warnings were issued by a number of countries but have subsequently been lifted many people fled from the coast in previously affected tsunami regions in response to warnings broadcast through local media and law enforcement organisations small tsunami were observed at a number of sites including the Cocos Islands where an amplitude of 20cm occurred Australian meterologists reported a tsunami-caused wave of similar magnitude hitting to the north and south of the Western Australian state capital Perth. preliminary reports by military and several news agencies indicate a wave 3m high struck Simeulue Island, 88km from the epicentre Damage Reports initial damage reports indicate the islands of Simeulue and Nias were the worst effected the majority of damage has been reported from the town of Gunungsitoli, on the island of Nias, with a population of around 27,000 local officials reported that over 70% of Gunungsitoli s buildings have collapsed with many trapped inside a fire was reported in Gunungsitoli on Tuesday morning following the earthquake the quake knocked out power at the city's biggest hospital and scared away many doctors and nurses a three metre tsunami has been reported to have caused extensive damage on Simeuleu Island both the airport and hospital have been affected to some degree electricity was cut across the northern areas of Sumatra the town of Aceh Singkil on the southwestern coast of Aceh province approximately 100km from the epicentre, has reportedly been destroyed Page 5 - GAPResponse

6 Insurance Losses It is too early to estimate the likely magnitude of insured losses from this earthquake. However, the areas which have suffered significant damage such as Simeulue and Nias islands have minimal insurance coverage. Preliminary reports from Indonesian cedants indicate that the main commercial city in North Sumatra, Medan has not suffered major damage. Page 6 - GAPResponse