Reviewed by USGSPhilippines54y ago
M5.1 earthquake 145 km ESE of Pondaguitan, Philippines
Sunday, January 7, 1973, 22:17:02 UTC · 5.683°N, 127.304°E
A magnitude 5.1 earthquake struck 145 km ESE of Pondaguitan, Philippines on Sunday, January 7, 1973, 22:17:02 UTC, at a depth of 79.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.9 on December 28, 1972.
- Magnitude
- 5.1
- Moderate · mb
- Depth
- 79 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
674 tons of TNT
That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.
Tectonic setting
19 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
79 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 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.2 on January 19, 1973. 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 217 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 · 164 km NW of this epicenter
- 8.01972 Mindanao, Philippines EarthquakeDecember 2, 1972 · 109 km NW of this epicenter
- 7.947 km ESE of Kalbay, PhilippinesMarch 14, 1913 · 157 km W of this epicenter
- 7.877 km E of Baculin, PhilippinesMay 25, 1943 · 188 km N of this epicenter
- 7.8161 km SE of Sarangani, PhilippinesApril 1, 1936 · 188 km SW of this epicenter
- 7.6101 km SE of Sarangani, PhilippinesDecember 16, 1910 · 182 km SW of this epicenter
- 7.6223 km ESE of Sarangani, PhilippinesJanuary 30, 1969 · 114 km S of this epicenter
- 7.5210 km SSE of Sarangani, PhilippinesAugust 17, 1912 · 278 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 22 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 · 300 km away
2,806 deathsSevere damage ($5–24M)tsunami
- 1913M7.8
Sangihe Island
14 Mar 1913 · 136 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
- 1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 257 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
- 1870
Mindanao: Davao,Blanco
4 Nov 1870 · 256 km away
4 deathsModerate damage ($1–5M)
- 1924M8.3
E Mindanao: Mati,Suriga
14 Apr 1924 · 127 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1903M7.8
Davao Gulf
28 Dec 1903 · 205 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.