This MASW project in Java Indonesia involved providing maps and models of seismic amplification and tsunami risk from a variety of regions in eastern Indonesia. These seismic hazards risk reduction assets, if implemented, have the potential to significantly reduce loss of life and infrastructure. The specific aim was to use Vs30 Measurements (S-Wave velocity at 30 meters depth) to quantify likely seismic shaking intensities and resonance frequencies in densely populated and rapidly developing areas. Noteworthy is the fact that all the places that the team investigated were previously flattened by earthquakes and inundated by tsunami, which will recur (Harris and Major, 2016).
The project team acquired 57 Vs30 and 48 HVSR measurements on 6 islands, excavated 8 paleotsunami trenches and documented imbricated beachrock boulder deposits at 18 different sites. These data revealed many vulnerable, densely populated areas highly susceptible to seismic wave amplification and tsunami hazards. Two earthquakes happened during the time of the project in the areas while the team was investigating, which provided a way to test their estimates of shaking intensity with real time MMI (Modified Mercalli Intensity) data. These data were used locally to modify zoning laws and building requirements. While at these sites the team also conducted other natural hazard risk reduction studies, including:
- Measurements and samples of paleo and historical tsunami deposits (Ashcraft 2021; Harris et al 2023)
- A potential sector collapse of Banda Api Volcano was also discovered (Ashcraft 2021)
- A publication in JGR resulted from using a Bayesian statistical approach to identify the likely epicenter, magnitude, and damage extent of the 1852 Banda Sea earthquake (Ringer et al 2021)
Art for Resilient Communities or ARC is a new initiative by Indonesian partners in this project. The team also contributed to this new disaster mitigation initiative. The work this project started now has a life of its own and continues through the efforts of several local trainees at all levels. Learn more.
