M 5.4 - 8 km SSE of New Mirpur, Pakistan

Tectonic Summary

The September 24, 2019, M 5.6 Pakistan earthquake likely occurred as the result of shallow reverse faulting near the convergent boundary between the India and Eurasia plates. Focal mechanism solutions are not well constrained but generally show reverse slip on a shallow or steeply dipping fault. Shallow east-west striking reverse faulting is consistent with the tectonics of the region. Earthquakes and active faults in northern Pakistan and adjacent parts of India and Afghanistan are the direct results of this collision. The boundary also produces the highest mountain peaks in the world, including the Himalayan, the Karakoram, the Pamir, and the Hindu Kush Ranges. As the India plate moves northward, it is being subducted or pushed beneath the Eurasia plate. At the location of this event, the India plate converges with the Eurasia plate at a rate of 39 mm/year.

Much of the compressional motion between these two colliding plates has been and continues to be accommodated by slip on a suite of major thrust faults that are at the Earth’s surface in the foothills of the mountains and dip north-northeastward beneath the ranges. These include the Main Frontal Thrust, the Main Central Thrust, the Main Boundary Thrust, and the Main Mantle Thrust. These faults have a sinuous trace as they arc across the foothills in northern India and into northern Pakistan. Active faulting is accommodated by a large system of faults.

A devastating M 7.6 event on October 8, 2005 occurred 160 km to the north of the September 24 event, also as a result of shallow reverse faulting. This event killed at least 86,000 people and caused extensive damage in northern Pakistan. Few other large events have occurred in recent decades in the immediate vicinity. Further afield, six events M 7 and greater have occurred over the preceding 40 years 400-500 km to the northwest in northeastern Afghanistan, mostly at intermediate depths of 100-250 km. The most recent event, one of the largest, was an M 7.5 earthquake in October 2015 that resulted in at least 395 fatalities, more than 1000 injuries, and the destruction of tens of thousands of buildings.