RAPID: Field Survey of the 27 September 2018 Sulawesi Tsunami

University Of Southern California, Los Angeles CA

Investigators

Abstract

This Rapid Response Research (RAPID) award funds a post-disaster tsunami survey of the 28 September 2018 Sulawesi magnitude Mw= 7.5 earthquake. It is estimated that his tsunami has killed in excess of 2,000 people, making it the deadliest tsunami initiated by a strike slip earthquake since the 2010 Haiti earthquake and tsunami. Only a small fraction of tsunamis are triggered by strike slip earthquakes such as this one, and very little data about this type of triggering mechanism are available. However, such earthquakes can occur in different locales in the western US, the Caribbean, and the Mediterranean, in addition to South East Asia. Scientists and engineers need to understand if there are unusual features of these strike-slip events which make them tsunamigenic, compared to the overwhelming majority of similar earthquakes which are not. The data collected by this reconnaissance team will be invaluable to the research community. Ultimately, it will help predict the risk to the U.S shoreline from strike slip earthquakes, and help make the U.S. better prepared for future tsunami events on our shores. The research team will: (1) take measurements of maximum inundation and flow depths; (2) analyze survivor videos; (3) measure co-seismic uplift, subsidence, and lateral spreading where observed; (4) document coastal landslides directly through a marine geology survey, or indirectly due to extreme localized runup spikes; (5) measure the type and severity of damage to different types of buildings and record what factors appeared to control damage levels; (6) collect information about survivor experiences and stories through interviews, if appropriate; and, (7) explore the human and community vulnerability and resilience factors at work in different places - what made a particular community resilient or vulnerable, what are the differential experiences of different types of people who experienced the tsunami? Data on tsunamis generated by strike slip earthquakes, such as this one, are rare, making up only approximately 10 percent of damaging tsunamis; therefore, it is particularly important to document this tsunami. A marine survey will help constrain the seismic source, so the triggering mechanism can be understood. The data obtained during this project will be archived through the NHERI DesignSafe Data Portal. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.