Near-field tsunami hazard map Padang, West Sumatra: Utilizing high resolution geospatial data and reseasonable source scenarios

Near-field tsunami propagation both in shallow water environments and bore-like wave propagation on land are conducted in this study to obtain fundamental knowledge on the tsunami hazard potential in the city of Padang, Western Sumatra, Republic of Indonesia. As the region proves a huge seismic moment deficit which has progressively accumulated since the last recorded major earthquakes in 1797 and 1833, this investigation focuses on most reasonable seismic sources and possibly triggered near-shore tsunamis in order to develop upgraded disaster mitigations programs in this densely-populated urban agglomeration located on the western shore of Sumatra Island. Observations from continuous Global Positioning Satellite (cGPS) systems and supplementary coral growth studies confirm a much greater probability of occurrence that a major earthquake and subsequent tsunami are likely to strike the region in the near future. Newly surveyed and processed sets of geodata have been collected and used to progress most plausible rupture scenarios to approximate the extent and magnitudes of a further earthquake. Based upon this novel understanding, the present analysis applies two hydronumerical codes to simulate most probable tsunami run-up and subsequent inundations in the city of Padang in very fine resolution. Run-up heights and flow-depths are determined stemming from these most plausible rupture scenarios. Evaluation of outcome and performance of both numerical tools regarding impacts of surge flow and bore-like wave fronts encountering the coast and inundating the city are thoroughly carried out. Results are discussed not only for further scientific purposes, i.e. benchmark tests, but also to disseminate main findings to responsible authorities in Padang with the objective to distribute the most probable dataset of plausible tsunami inundations as well as to address valuable insights and knowledge for effective counter measures, i.e. evacuation routes and shelter building. Following evacuation simulations based on rational assumptions and simplifications reveal a most alerting result as about 265.000 people are living in the highly exposed potential tsunami inundation area in the city of Padang of which more than 95.000 people will need more than 30 min. to evacuate to safe areas.DFGBMB

Untersuchung der Tsunami-Vulnerabilität von Küstenökosystemen an der Andamanenküste Thailands - Potential & Grenzen eines GIS- und fernerkundungsgestützten Ansatzes auf lokaler Skala

The thesis deals with the assessment of tsunami vulnerability and resilience of coastal ecosystems at the Andaman coast of Thailand by applying a remote sensing based approach. Object-oriented image analysis, change detection techniques and field investigations are used to a) retrospectively investigate the spatial patterns of tsunami vulnerability and b) to evaluate the potential and limitations of using high-resolution imagery (here IKONOS data) in the field of tsunami vulnerability and risk analysis. The results show that vulnerability varied strongly in space and in ecosystem type: although being little exposed to tsunamis, mangrove forests locally turned out to be a vulnerable ecosystem. Furthermore, the study revealed that remote sensing techniques can be an effective tool for the assessment of tsunami vulnerability. Furthermore, a valuable (geo)-data basis was created serving as a flexible starting point for further investigations on ecological and socio-ecological vulnerability.Die Arbeit widmet sich der Thematik der Abschätzung der Tsunami-Vulnerabilität und Resilienz von Küstenökosystemen an der Andamanküste Thailands unter Nutzung eines fernerkundungsbasierten Ansatzes. Feldmessungen, objektorientierte Bildanalyse sowie Verfahren der Veränderungsdetektion werden dabei zur retrospektiven Abschätzung der Tsunami-Vulnerabilität eingesetzt. Dabei werden auch die Potentiale und Grenzen von Fernerkundungsanwendungen im Kontext der Vulnerabilitäts- und Risikoanalyse beurteilt. Die Ergebnisse zeigen, dass die Vulnerabilität räumlich und je nach Ökosystemtyp stark variiert: Mangrovenwälder haben sich beispielsweise als gering exponiertes, lokal jedoch als vulnerables Ökosystem herausgestellt. Die Studie verdeutlicht weiterhin, dass Fernerkundung ein effektives Werkzeug für die Abschätzung der Tsunamivulnerabilität darstellt, wobei eine Geodatenbank generiert wurde, die sich als Anknüpfungspunkt für weitergehende Studien zur ökologischen und sozio-ökologischen Vulnerabilität eignet