Inundation distances and run‐up measurements from ASTER, QuickBird and SRTM data, Aceh coast, Indonesia

Abstract

The massive 26 December 2004 earthquake and tsunami affected a large geographic region in the Indian Ocean basin, hitting Indonesia's Aceh province on the island of Sumatra particularly hard. In this study, tsunami inundation distances and run‐up elevations on the NW Sumatran coast are assessed at a regional scale using remotely sensed data (ASTER, QuickBird and SRTM). Using satellite data in disaster zones allows tsunami scientists to access data in difficult areas (logistically and politically), along with the other benefits that such data has to offer (e.g. spectral and spatial). Field work rapidly following the tsunami allowed the collection of samples, elevation data and other information through interviews with survivors that validated the remotely sensed observations. Median run‐up elevations extracted from SRTM and ASTER generated digital elevation models (DEMs) for the Banda Aceh area were 16 m and 9.7 m above sea level respectively, and field measurements averaged 9 m. In Meulaboh, median run‐up elevations were 9 m (SRTM) and 6.6 m (ASTER) which are close to the 10–15 m range determined in the field. Run‐up elevations at Jantang have a bimodal distribution with peaks that correspond to inundation limits in the floodplains (∼10 m in both the SRTM and ASTER data) and cliffs (32 m in the ASTER and less well‐defined in the SRTM data). Slope maps generated from SRTM and ASTER DEMs show that the inundation limit rarely exceeds slopes of 4°. Using the Aceh area as a control, SRTM and ASTER data and the range of possible products derived from them is here taken as potential suitable tool for computer inundation models that aid in evacuation planning.

Acknowledgements

The Institute of Geology (P. Allen) at the Swiss Federal Research Institute (ETH) in Zürich, Switzerland supported this study while BGM was visiting. Additional funding was provided by the Vassar College Environmental Sciences Research Fund. Field work in Aceh would not have been possible without the support of Gegar Prasetya and others at BPPT, Indonesia and the two UNESCO sponsored International Tsunami Survey Teams. A. Densmore at the ETH and M. Cunningham at Vassar provided excellent discussions at the formative stages of this project and the comments of two anonymous reviewers greatly improved the manuscript.