M7.3 earthquake 68 km W of Gadung, Philippines

Friday, July 23, 2010, 22:08:11 UTC · 6.718°N, 123.409°E

A magnitude 7.3 earthquake struck 68 km W of Gadung, Philippines on Friday, July 23, 2010, 22:08:11 UTC, at a depth of 607.1 km (deep). USGS received 20 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M7.5 on March 5, 2002.

Magnitude: 7.3; Major · mwc
Depth: 607 km; Deep
Felt reports: 20; Max intensity IV
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search area

In context

How big was it, and why here?

Energy released

1.3 megatons of TNT

That is about 89 times the Hiroshima bomb. It released about 2,818 times the energy of a magnitude 5.0.

Tectonic setting

424 km

from the nearest mapped plate boundary, between the Philippine Sea and Sunda plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: deep

607 km

Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.

Did You Feel It?

Where it was felt

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Cagayan, Northern Mindanao, Philippines	III · Weak	3	651 km
Alabel, Southern Mindanao, Philippines	IV · Light	2	644 km
Davao, Southern Mindanao, Philippines	III · Weak	2	656 km
Manila, National Capital Region, Philippines	II · Weak	2	1097 km
Purikay, Central Mindanao, Philippines	IV · Light	1	611 km
Abucay, Bicol, Philippines	IV · Light	1	921 km
Tanauan, Eastern Visayas, Philippines	IV · Light	1	797 km
Ternate, Maluku Utara, Indonesia	III · Weak	1	995 km
Panabo, Southern Mindanao, Philippines	III · Weak	1	660 km
Kadingilan, Northern Mindanao, Philippines	II · Weak	1	636 km
Tagbilaran, Central Visayas, Philippines	II · Weak	1	690 km
Palo, Eastern Visayas, Philippines	II · Weak	1	800 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 200 km

USGS lists 36 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M7.6 on July 23, 2010. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 482 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 28 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 8,673 recorded deaths. The most severe:

1976M8.0
Mindanao: S
16 Aug 1976 · 89 km away · intensity VI
8,000 deaths$134 million damagetsunami
1955M7.4
Mindanao: Lanao,Ozamiz,Cotabato
31 Mar 1955 · 108 km away · intensity VIII
465 deaths$5 million damagetsunami
1928M7.4
Cotabato,N Coast Of Illana Bay
19 Dec 1928 · 92 km away · intensity VII
97 deathsModerate damage ($1–5M)tsunami
1918M8.3
Mindanao: Cotabato
15 Aug 1918 · 146 km away · intensity X
52 deathsSevere damage ($5–24M)tsunami
1925M6.8
W. Luzon Island, Philippines
5 May 1925 · 298 km away · intensity IX
17 deathsModerate damage ($1–5M)tsunami
2002M7.5
Mindanao
5 Mar 2002 · 120 km away
15 deaths$2 million damagetsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers