Magnitude 7.6 - MORO GULF, MINDANAO, PHILIPPINES
2010 July 23 22:51:12 UTC
Earthquake Details
- This event has been reviewed by a seismologist.
| Magnitude | 7.6 |
|---|---|
| Date-Time |
|
| Location | 6.470°N, 123.532°E |
| Depth | 583.8 km (362.8 miles) |
| Region | MORO GULF, MINDANAO, PHILIPPINES |
| Distances | 120 km (75 miles) SW of Cotabato, Mindanao, Philippines 145 km (90 miles) S of Pagadian, Mindanao, Philippines 160 km (100 miles) ESE of Zamboanga, Mindanao, Philippines 930 km (580 miles) SSE of MANILA, Philippines |
| Location Uncertainty | horizontal +/- 13.8 km (8.6 miles); depth +/- 8 km (5.0 miles) |
| Parameters | NST=408, Nph=422, Dmin=236.3 km, Rmss=1.17 sec, Gp= 14°, M-type=teleseismic moment magnitude (Mw), Version=R |
| Source |
|
| Event ID | us2010zbca |
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Earthquake Summary
Felt Reports
Felt (IV PIVS) at General Santos; (III PIVS) at Davao, Malita, Padada and Santa Maria; (II PIVS) at Ayala, Butuan, Cagayan de Oro, Dipolog, Isabela, Matanao, Soccoro, Surigao and Tacloban; (I PIVS) at Midsayap. Also felt at Digos, Koronadal, Mati, Polomolok, Puricay and Recodo. Felt (III PIVS) at Palo, Leyte. Felt (II PIVS) at Cebu, Cebu. Felt (II PIVS) at Calinan, Makati and Palanan, Luzon. Also felt at Manila. Felt (II PIVS) at Bayawan, Negros. Also felt at Bacolod. Felt at (I PIVS) at Aklan and Makato, Panay. Also felt at Iloilo.
Tectonic Summary
The July 23, 2010 earthquakes in the Moro Gulf, south of Mindanao, Philippines,
occurred within the inclined seismic zone defining the deep limit
of the Molucca Sea micro plate beneath the Celebes Sea basin.
Northeastern Indonesia and southern Philippines are characterized
by complex tectonics in which motions of numerous small plates accommodate
the large-scale convergence between the Philippine Sea and Sunda plates.
In the region of today's earthquake, the Philippine Sea plate moves west-northwest
with respect to the Sunda plate at a velocity that various models would place
in the 60-110 mm/year range.
Locally, arc-arc collision is occurring between the Sangihe microplate
and the Philippine Sea plate, wedging between them the Molucca Sea micro plate,
which subducts beneath both (i.e. to the east and west)
and forms an inverted-U-shaped seismic zone.
At the latitude of the July 23 earthquakes, the top of the Molucca Sea microplate
is at a depth of about 150 km beneath the earth's surface.
Seismicity within the Molucca Sea micro plate is active to depths
of approximately 260 km to the east and 650 km to the west.
The tectonic setting of this region is unique in that it is the only global example
of an active arc-arc collision consuming an oceanic basin via subduction in two directions.
The July 23rd events occurred in response to stresses generated by the slow distortion of the Molucca Sea micro plate at depth, rather than on the shallower interfaces with the overriding Sanglehe and Philippine Sea plates, active boundaries in this region near the earth's surface.
Earthquakes that have focal depths greater than 300 km are commonly termed "deep-focus" earthquakes. Deep-focus earthquakes cause less damage on the ground surface above their foci than is the case with similar magnitude shallow-focus earthquakes, but large deep-focus earthquakes may be felt at great distance from their epicenters. The largest recorded deep-focus earthquake had a magnitude of 8.2, and occurred deep beneath Bolivia in June 1994. Over the past 50 years, approximately 50 earthquakes with magnitudes of M7 or more have occurred at depths greater than 500 km; just two of these were located in the same region as today's events.
Earthquake Maps
Scientific & Technical Information
Historic Moment Tensor Solutions- Preliminary Earthquake Report
- U.S. Geological Survey, National Earthquake Information Center:
World Data Center for Seismology, Denver
