Rapid assessment of morphological change caused by catastrophic tsunamis: Integrated geological remote sensing and field investigation of the March 2011 Tohoku-oki Tsunami
Abstract
Rapid assessment of tsunami impact is key to hazard characterisation and disaster mitigation in the aftermath of catastrophic tsunamis. Investigation of landscape changes caused by tsunamis is also vital to better understand their process of operation and prepare for the effects of future events. However, as many of these geomorphological and geological features are ephemeral, being easily destroyed by natural and anthropogenic activity after the event, timely investigation is essential. The increasing availability of remotely-sensed data provides a means of rapidly assessing landscape changes caused by tsunamis and when integrated with targeted field investigation acts as a crucial tool in tsunami characterisation. Following the catastrophic Tohoku-oki tsunami of March 2011, the British Geological Survey obtained high resolution satellite imagery (Ikonos, Quickbird, WorldView), aerial photography and LiDAR through the International Charter on Space and Major Disasters. Comparison of pre- and post-event data allowed the identification of inundated areas; debris source and deposition sites and flow direction indicators- building a picture of tsunami flow characteristics and resultant landscape impacts. Field investigation of selected sites within the Sendai area was undertaken in June 2011 in order to validate the interpretation of remotely-sensed data and gather additional information on flow depth and sedimentological characteristics. Ruggedized laptops equipped with the BGS.SIGMAmobile digital mapping system and loaded with the pre-interpreted geological remote sensing data aided the integration of pre-field data interpretation and field-investigation. The combination of pre-fieldwork interpretation of remotely-sensed data and field investigation revealed inundation limits up to 4.5km inland, flow depths of 11m and wide-ranging transport of debris. Crucially, timely and targeted investigation of landscape changes caused by the Tohoku-oki event was possible.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMNH41C..05J
- Keywords:
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- 4564 OCEANOGRAPHY: PHYSICAL / Tsunamis and storm surges;
- 4313 NATURAL HAZARDS / Extreme events;
- 4337 NATURAL HAZARDS / Remote sensing and disasters