Mapping severe damage to land cover following the 2004 Indian Ocean tsunami using moderate spatial resolution satellite imagery

Abstract

Visual analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) 250m before‐and‐after event imagery along 11 335 km of South East Asia and East Africa's coastline identified major changes to land cover along 1 220 km of coast caused by the tsunami of 26 December 2004. Over 81 000 ha of land were mapped as lost or severely damaged. High spatial resolution images (10–32 m) from the Terra satellite's Advanced Spaceborne Thermal Emission and Reflection Radiometer, Disaster Monitoring Constellation's Surrey Linear Imager and the Landsat Enhanced Thematic Mapper (ETM) provided verification. Area estimates of damaged land from MODIS were within 17% of the estimates made using high spatial resolution systems. Errors of commission and omission were estimated at 14% and 31%, respectively. The correlation between damage estimates from MODIS and high spatial resolution systems resulted in an R ² of 0.73 at the 99.5% confidence level, with MODIS proving especially effective at mapping tsunami‐damaged areas greater in size than 150 ha. Correcting the original area estimate to account for errors of omission and commission using the regression model gave a revised figure of 103 854 ha of land damaged. Land cover types could not be assigned from the MODIS pre‐ and post‐disaster image pairs, but interpretation of pre‐disaster ETM imagery for the damaged areas indicated that around 5% was previously classed as barren, 11% as urban, 14% forest and 70% rural. The study provides confirmation that moderate resolution satellite imagery can provide rapid assessments of severe damage to land resources (though not cover type), as well as confirmation of non‐affected areas, over very large geographical regions in the aftermath of natural disasters such as the tsunami.

Acknowledgements

Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images were courtesy of National Aeronautics and Space Administration (NASA), Landsat Enhanced Thematic Mapper (ETM) were courtesy of NASA and United States Geological Survey (USGS). The Disaster Monitoring Constellation kindly provided the Survey Linear Imager (SLIM6) imagery used by German Aerospace Centre (DLR). The authors would particularly like to thank Thomas Kemper from DLR who made available the high spatial resolution DMC analysis of land cover change over Sumatra. We would also like to thank Freddy Dezeure and Jean‐Paul Malingreau who provided overall co‐ordination for the JRC's response to the tsunami, Alessandro Annunziato who provided excellent management of the JRC tsunami website, Frederic Achard who provided advice on the moderate resolution image analysis, the core partners in the RESPOND alliance including United Nations Institute for Training and Research Operational Satellite Applications Programme (UNOSAT), the provider of satellite data for United Nations agencies, Infoterra UK, German Aerospace Centre (DLR), MAPACTION UK and SERTIT France and the anonymous reviewer who provided constructive criticism.