M 7.1 - 137 km WNW of Ternate, Indonesia

  • 2001-02-24 07:23:48 (UTC)
  • 1.271°N 126.249°E
  • 35.0 km depth

Tectonic Summary

The February 24, 2001, M 7.1 Molucca Sea earthquake occurred as the result of shallow oblique reverse faulting within the complex active tectonic zone of eastern Indonesia. The focal mechanism solutions indicate that rupture occurred on either a northeast- or southwest-striking, moderately dipping reverse fault. Slip on a fault of either orientation is consistent with the compressional tectonics implied by the faulting mechanism and earthquake depth. At this location, the Sunda and Philippine Sea plates are converging in an east-west direction at a rate of approximately 109 mm/yr. In the broader region surrounding this event, the north-south convergence between the Australia and Sunda plates, and the east-west convergence between Sunda and the Pacific and Philippine Sea plates, together drive the motion of small microplates that are situated among them. Of these local microplates, the Febrary 24th earthquake occurred near the boundary between the northern edge of the Birds Head microplate and the larger Sunda plate, just east of the Molucca Sea microplate.

Frequent volcanic eruptions and earthquakes testify to the active and complex tectonic processes in this region. The distribution of small ocean basins, continental fragments, remnants of ancient magmatic arcs and numerous subduction complexes that make up the Indonesian region point to an equally active and complex tectonic history. There have been five other M 7+ earthquakes within 200 km of the February 24th event over the preceding 40 years. The largest was a M 7.6 earthquake in August 1986, approximately 30 km to the north. The most damaging event within the vicinity was a M 6.9 earthquake in January 1994, roughly 175 km to the east, which resulted in at least 7 fatalities and 40 injuries.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)

For More Information