With a population of over 250 million people, Indonesia is the fourth most populous country in the world (United Nations, 2013). Indonesia also experiences more earthquakes than any other country in the world (USGS, 2015). Its borders encompass one of the most active tectonic regions on Earth including over 18 000 km of major tectonic plate boundary, more than twice that of Japan or Papua New Guinea (Bird, 2003). The potential for this tectonic activity to impact large populations has been tragically demonstrated by the 20004 Sumatra earthquake and tsunami. In order to inform earthquake risk reduction in Indonesia, a new national earthquake hazard map was developed in 2010 (Irsyam et al., 2010). In this report historical records of damaging earthquakes from the 17th to 19th centuries are used to test our current understanding of earthquake hazard in Indonesia and identify areas where further research is needed. In this report we address the following questions:
- How well does our current understanding of earthquake hazard in Indonesia reflect historical activity?
- Can we associate major historical earthquakes with known active faults, and are these accounted for in current assessments of earthquake hazard?
- Does the current earthquake hazard map predict a frequency and intensity of shaking commensurate with the historical record?
- What would the impact of these historical earthquakes be if they were to reoccur today?
To help answer questions like these, this report collates historical observations of eight large earthquakes from Java, Bali and Nusa Tenggara between 1699 and 1867. These observations are then used to:
- Identify plausible sources for each event;
- Develop ground shaking models using the OpenQuake Engine (GEM Foundation, 2015);
- Assess the validity of the current national seismic hazard map; and
- Estimate fatalities were the historical events to occur today using the InaSAFE (InaSAFE.org, 2015) software.
