Reviewed by USGSPhilippines72y ago
M6.3 earthquake 7 km W of Marogong, Philippines
Thursday, March 31, 1955, 20:52:49 UTC · 7.674°N, 124.081°E
A magnitude 6.3 earthquake struck 7 km W of Marogong, Philippines on Thursday, March 31, 1955, 20:52:49 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on March 31, 1955.
- Magnitude
- 6.3
- Strong · mw
- Depth
- 35 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
49 kilotons of TNT
That is about 3 times the Hiroshima bomb. It released about 102 times the energy of a magnitude 5.0.
Tectonic setting
347 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: 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 100 km
USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M6.3 on April 10, 1955. 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 83 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.31918 Mindanao, Philippines EarthquakeAugust 15, 1918 · 238 km S of this epicenter
- 8.11924 Mindanao, Philippines EarthquakeApril 14, 1924 · 258 km SE of this epicenter
- 7.410 km ESE of Basak, PhilippinesDecember 19, 1928 · 109 km S of this epicenter
- 7.4Mindanao, PhilippinesMarch 31, 1955 · 102 km W of this epicenter
- 7.312 km SSW of Kipit, PhilippinesOctober 20, 1942 · 180 km W of this epicenter
- 7.222 km ESE of Bobon, PhilippinesJanuary 1, 1919 · 286 km E of this epicenter
- 7.25 km ESE of Veruela, PhilippinesJune 13, 1929 · 216 km E of this epicenter
- 7.25 km NW of Kadingilan, PhilippinesMarch 2, 1923 · 87 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 34 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 660 recorded deaths. The most severe:
- 1955M7.4
Mindanao: Lanao,Ozamiz,Cotabato
31 Mar 1955 · 102 km away · intensity VIII
465 deaths$5 million damagetsunami
- 1928M7.4
Cotabato,N Coast Of Illana Bay
19 Dec 1928 · 109 km away · intensity VII
97 deathsModerate damage ($1–5M)tsunami
- 1918M8.3
Mindanao: Cotabato
15 Aug 1918 · 238 km away · intensity X
52 deathsSevere damage ($5–24M)tsunami
- 1925M6.8
W. Luzon Island, Philippines
5 May 1925 · 236 km away · intensity IX
17 deathsModerate damage ($1–5M)tsunami
- 1897M8.7
Mindanao, Zamboanga, Sulu, Isabela
21 Sep 1897 · 296 km away · intensity IX
13 deathsSevere damage ($5–24M)tsunami
- 1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 212 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.