M5.3 earthquake 78 km ESE of Pondaguitan, Philippines

Monday, March 5, 1973, 23:20:26 UTC · 6.154°N, 126.853°E

A magnitude 5.3 earthquake struck 78 km ESE of Pondaguitan, Philippines on Monday, March 5, 1973, 23:20:26 UTC, at a depth of 84.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.5 on February 13, 1973.

Magnitude: 5.3; Moderate · mb
Depth: 84 km; Intermediate
Felt reports: 0; Did You Feel It?
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

1 kilotons of TNT

That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.

Tectonic setting

53 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: intermediate

84 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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 75 km

USGS lists 8 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M6.0 on March 9, 1973. 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 247 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 25 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 246 recorded deaths. The most severe:

1913M7.8
Sangihe Island
14 Mar 1913 · 120 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
1928M7.4
Cotabato,N Coast Of Illana Bay
19 Dec 1928 · 295 km away · intensity VII
97 deathsModerate damage ($1–5M)tsunami
1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 206 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
1870
Mindanao: Davao,Blanco
4 Nov 1870 · 186 km away
4 deathsModerate damage ($1–5M)
1924M8.3
E Mindanao: Mati,Suriga
14 Apr 1924 · 55 km away · intensity IX
Severe damage ($5–24M)tsunami
1903M7.8
Davao Gulf
28 Dec 1903 · 133 km away · intensity VIII
Moderate damage ($1–5M)

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

Nearby trackers