Seismic Activity in the Banda Sea: The 2012 M7.1 Earthquake and Regional History

The Banda Sea region, located in eastern Indonesia, lies within one of the world's most tectonically complex zones. It forms part of the Banda Arc, where the Australian Plate subducts beneath the Eurasian Plate. This convergence produces frequent intermediate-depth earthquakes, often occurring between 100 and 200 km depth due to the descending slab.

On 10 December 2012 at 16:53 local time, a magnitude 7.1 earthquake struck the Banda Sea at a depth of 155 km. The event's epicenter was situated in an area that has experienced multiple comparable shocks in recent decades, reflecting persistent strain release along the subducting slab.

Seismicity records since 2000 highlight a cluster of strong events within tens of kilometers of the 2012 hypocenter. These include a magnitude 7.1 event on 2 March 2005 located 11 km away, a magnitude 7.3 shock on 24 June 2019 situated 73 km distant, a magnitude 7.6 earthquake near Pulau Pulau Tanimbar on 9 January 2023 positioned 61 km away, and another magnitude 7.1 event on 8 November 2023 occurring 33 km from the 2012 site. Such proximity underscores the repeated activation of the same fault segments within the subducted lithosphere.

The intermediate depths of these quakes typically limit surface damage compared with shallow crustal events, yet they can still generate felt shaking across nearby islands. The Banda Sea's history of M7+ earthquakes demonstrates ongoing plate boundary deformation that has persisted for millions of years, driven by the ongoing collision between the Australian continent and the Banda Arc.

References

• USGS Earthquake Catalog (events 2005–2023)
• Incorporated Research Institutions for Seismology (IRIS) event data
• Tectonic framework descriptions from peer-reviewed literature on the Banda Arc subduction zone