Mw 6.0 Earthquake Strikes Jakarta

Mw 6.0 Earthquake Strikes Jakarta

  • EOS News
23 Jan 2018

An intraslab magnitude-6.0 earthquake struck off the coast of Java, Indonesia (Source: Yves Descatoire/EOS)

A magnitude-6.0 earthquake struck Jakarta, Indonesia on 23 January 2018 at approximately 1:30pm (Singapore time). Based on information provided by the United States Geological Survey (USGS), the quake occurred in the Indian Ocean, about 154 kilometres (km) off the southwest coast of Java at a depth of about 44 km.

According to the Indonesia’s Agency for Meteorology, Climatology and Geophysics of Indonesia (BMKG), the earthquake originated from an oblique thrust fault. BMKG recorded 20 aftershocks within two hours of the quake.

The Mw 6.0 earthquake caused ground shaking throughout West and Central Java, and in Southern Sumatra. According to citizen reports, the earthquake was felt with intensity IV-V (light to moderate on the Modified Mercalli Intensity Scale) in Jakarta and BPogor, III (weak) in Bandung and Southern Sumatra, and II (weak) in Bantul, Jogyakarta. Photos showing earthquake damage in Lebak, West Java, - the area closest to the quake’s epicentre - have been circulating on social media.

The impact of this earthquake on places like Lampung and Jogyakarta - about 495 km from the epicentre - indicates that the quake occurred at a moderate depth. Such moderately deep earthquakes allow for the release of energy across relatively long distances compared to shallow earthquakes with the same magnitude.

The location of the earthquake’s epicentre indicates that it was an intraslab quake, originating within the Indian Ocean plate as it subducted underneath the Eurasian plate. Intraslab earthquakes typically release more high frequency energy than earthquakes that occur at the boundary of a tectonic plate.