Preferred Hazard Information

Intensities reached VIII+ on the MMI scale – very well built structures received slight damage. Older buildings suffered great damage. The damage seen corresponds to VII and VII+ and perhaps very isolated VIII locations on the MMI scale.

5 aftershocks > Mw5.0 have occurred, however the foreshock sequence including the Mw6.4 foreshock mean well over 35 magnitude 4 and 5 earthquakes have continued to pepper the region NW and SE of the epicenter, 546 events have been recorded. The fault sense can be seen well from BMKG data. We are currently waiting for more information with respect to ground motions and spectral response. A very small tsunami was expected, and this caused initial issues for evacuation. There exists significant variation in intensities.

Vulnerability & Exposure

The time of day at 19:46 is one of the big uncertainties in this event with models of population not well constrained for Lombok and Bali. 74% of people were expected to be indoors, however it looks as though this number could be as low as 40% with weather conditions on the day. The area is highly populated with Lombok home to around 3.5 million people. The capital stock associated with construction is comparatively low and much poor vulnerable construction has been seen due to a lack of significant past earthquake activity on Lombok. The GDP is around half of the national average. (GDP per capita and population density shown). The population in the region of over VI is somewhere between 2.7 and 4.0 million people.

The GDP in the region over Int VI- is ca. 7.6 bn USD. The Capital stock over VI- is in the order of 19 bn USD including building and non-building infrastructure.

Building Damage

The quality of housing differs across Lombok, but most (ca. 90%) is clay brick or concrete. North Lombok however builds of 12.7% bamboo and other construction (14.9% in rural, 2.6% in Urban). The poor clay construction seems to have been most affected. Considering the vulnerability of the local building stock, over 30,000 buildings are expected to have been damaged or destroyed. Damage distributions are currently being collected by authorities. Many roof collapses have been seen where connections to the structure have failed. Similarly poor quality residential construction appears to be most affected.