MCEER Earthquake Reconnaissance Investigation
Preliminary Field Report: Post-Tsunami Urban Damage Survey in Thailand, Using the VIEWS Reconnaissance System
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On 26 Dec 2004, 00:58:53 UTC, a magnitude 9.0 earthquake occurred off the west coast of northern Sumatra, Indonesia. The epicenter was located beneath the Indian Ocean at 3.307°N 95.947°E. The earthquake triggered a series of tsunamis in the region that devastated communities along thousands of miles of exposed coastline. Ranked as one of the most catastrophic events in recent times, the earthquake and subsequent tsunami caused significant damage in 11 countries and resulted in over 200,000 deaths. Countless others were rendered homeless, or left without basic lifelines and amenities.
The Multidisciplinary Center for Earthquake Engineering Research (MCEER) joined a multi-lateral Thailand-Japanese reconnaissance team to investigate the effects of the Tsunami disaster in Thailand. Of the affected nations, Thailand was selected as the destination based on a preliminary assessment of potential casualties in the region by ImageCat using remote sensing data1 and media reports of >5,300 deaths, destruction of multiple tourist destinations, and >US$500 million damage to the nations shrimp industry. The reconnaissance team was led by Professor Fumio Yamazaki of Chiba University in Chiba, Japan and Dr. Pennung Warnitchai of the Asian Institute of Technology in Bangkok, Thailand. Shubharoop Ghosh of ImageCat, Inc. represented MCEER. Other researchers in the team included Dr. Masahiko Honzawa of Japan International Cooperation Agency (JICA), and Dr. Masashi Matsuoka of Earthquake Disaster Mitigation Research Center (EDM), Kobe, Japan.
The objective of this field deployment was to collect perishable information about building and lifeline damage characteristics. The field-based damage assessment was conducted using the VIEWS (Visualizing the Impacts of Earthquakes With Satellites). These ground-based observations can be later used to validate damage characteristics identified on satellite imagery. It is envisioned that such perishable data will be invaluable for future research in evaluating damage from Tsunami hazards.
VIEWS is a notebook-based system, which integrates GPS-registered digital video footage, digital photographs and observations with high-resolution satellite imagery collected before and after a disaster. VIEWS was previously used in reconnaissance activities following the 2003 Bam, Iran earthquake, Hurricane Charley and Hurricane Ivan that hit the Gulf coast in 2004, and the Niigata, Japan earthquake in October 2004.
The following preliminary field report begins with a brief overview of the field study sites. It goes on to document damage survey activities that were conducted, together with methodologies employed for data collection. It includes a discussion on the satellite imagery and other data that were available from various sources. The resulting data sets from the survey are presented. The report summarizes preliminary findings through a selection of illustrative examples, which were extracted using the MCEER funded D-VRS system.
The post-tsunami damage assessment was conducted in three south-western provinces of Thailand (Figure 1): Phang Nga; Krabi; and Phuket. Survey site selection was made in consultation with Dr. Pennung Warnitchai of the Asian Institute of Technology, and was based on media reports of areas experiencing severe damage (particularly where the key industries of tourism and fisheries were hard hit), and areas for which “before” and “after” Quickbird satellite imagery was available.
The field survey was conducted using the VIEWS system from a moving vehicle and on foot (see Figure 2), depending on vehicular access to impacted areas. Access to selected study areas in general did not prove to be a significant limitation; admittance to the heavily damaged sites did not require special authorization. However, the areas surveyed within the three provinces were spread wide apart, and traveling to and from the study sites proved to be time consuming.
To conduct survey from a moving vehicle, a van was selected by the team, since it provided increased elevation above street level, and better coverage by avoiding obstructions in the foreground. The vehicle was driven at around 10-15 mph, as this speed allowed the video coverage and stills to be obtained with a lesser degree of aberration, while enabling a large geographic extent to be covered. More in-depth damage assessments were conducted on foot.
For this deployment, a new data collection approach was adopted (Figure 2)
by deploying three video cameras that simultaneously captured footage for
three directions (front, left, and right) in some heavily affected areas.
This streamlined the video collection process and provided a wider view of
the area. An alternative handheld-based approach was also tested for collecting
GPS points. A Garmin iQue® Handheld with built-in GPS receiver was used
to collect GPS points in the survey sites where VIEWS was deployed. 11 hours
of digital video footage was recorded during the reconnaissance route that
covered >50 kms. A library of about 1500 digital photographs was also collected
by the team.
|(a) VIEWS deployment with one camera||
(b) VIEWS deployment with three cameras
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