Reviewed by USGSPhilippines70y ago
M7.3 earthquake 146 km SE of Pondaguitan, Philippines
Tuesday, September 24, 1957, 08:21:14 UTC · 5.327°N, 127.005°E
A magnitude 7.3 earthquake struck 146 km SE of Pondaguitan, Philippines on Tuesday, September 24, 1957, 08:21:14 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on May 25, 1943.
- Magnitude
- 7.3
- Major · mw
- Depth
- 35 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
1.1 megatons of TNT
That is about 75 times the Hiroshima bomb. It released about 2,371 times the energy of a magnitude 5.0.
Tectonic setting
57 km
from the nearest mapped plate boundary, between the Philippine Sea and Sunda plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
35 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
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 2 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.1 on September 25, 1957. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 113 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11924 Mindanao, Philippines EarthquakeApril 14, 1924 · 172 km NW of this epicenter
- 7.947 km ESE of Kalbay, PhilippinesMarch 14, 1913 · 126 km W of this epicenter
- 7.877 km E of Baculin, PhilippinesMay 25, 1943 · 229 km N of this epicenter
- 7.8161 km SE of Sarangani, PhilippinesApril 1, 1936 · 137 km SW of this epicenter
- 7.6101 km SE of Sarangani, PhilippinesDecember 16, 1910 · 132 km SW of this epicenter
- 7.5210 km SSE of Sarangani, PhilippinesAugust 17, 1912 · 227 km SW of this epicenter
- 7.5273 km N of Tobelo, IndonesiaOctober 23, 1914 · 168 km SE of this epicenter
- 7.462 km E of Baculin, PhilippinesNovember 11, 1921 · 237 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 18 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,955 recorded deaths. The most severe:
- 1856
Sangihe Pulau (Volcanic)
2 Mar 1856 · 249 km away
2,806 deathsSevere damage ($5–24M)tsunami
- 1913M7.8
Sangihe Island
14 Mar 1913 · 98 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
- 1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 234 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
- 1870
Mindanao: Davao,Blanco
4 Nov 1870 · 257 km away
4 deathsModerate damage ($1–5M)
- 1924M8.3
E Mindanao: Mati,Suriga
14 Apr 1924 · 142 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1903M7.8
Davao Gulf
28 Dec 1903 · 217 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.