A Quantitative Reappraisal of Historical Earthquakes in Indonesia from Uniformly Assessed Macroseismic Observations from the Dutch Colonial Period

A critical qualitative and quantitative analysis of primary sources is key to validate, improve, and supplement the census of historical earthquakes in Indonesia, which in turn is key to the assessment of regional seismic hazard. We propose to collect documentary evidence from the Dutch colonial period for Sumatra and Java. We will prepare an open-access database of our observations. When complimentary modern observations are available, these datasets will be jointly inverted to estimate effective intensity magnitudes. We will also utilise near- and far-field documentary estimates of run-up to forward model and constrain the source of the very large 1907 Simeulue tsunami earthquake.

In the past year we revisited historical documentary accounts and new seismological data for the 1907 Sumatra earthquake, and uncovered two separate events within an hour of each other, including one that was tsunamigenic. Extracting numerical constraints from the same data, we forward modelled the Indian Oceanwide tsunami. This allowed us to constrain the seismic moment magnitude, and to estimate the geometry of the causative rupture. We will publish our results in FY2017-18. We will also publish the Gempa Nusantara Macroseismic Database, our new catalogue of uniformly assessed macroseismic data from Indonesia from 1800 until 1939 along with an online searchable version.

Project Years: 

2016, 2017