Reviewed by USGSPhilippines54y ago
M4.8 earthquake 106 km SE of Pondaguitan, Philippines
Thursday, March 15, 1973, 02:05:15 UTC · 5.620°N, 126.787°E
A magnitude 4.8 earthquake struck 106 km SE of Pondaguitan, Philippines on Thursday, March 15, 1973, 02:05:15 UTC, at a depth of 65.0 km (shallow). It is the strongest earthquake within 300 km since an M5.5 on March 12, 1973.
- Magnitude
- 4.8
- Light · mb
- Depth
- 65 km
- Shallow
- 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
239 tons of TNT
That is about 1/63 of the Hiroshima bomb. A magnitude 5.0 releases about 2 times more energy.
Tectonic setting
77 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
65 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 50 km
USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M5.3 on April 13, 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 241 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 · 131 km NW of this epicenter
- 8.01972 Mindanao, Philippines EarthquakeDecember 2, 1972 · 91 km N of this epicenter
- 7.947 km ESE of Kalbay, PhilippinesMarch 14, 1913 · 100 km W of this epicenter
- 7.877 km E of Baculin, PhilippinesMay 25, 1943 · 202 km N of this epicenter
- 7.8161 km SE of Sarangani, PhilippinesApril 1, 1936 · 157 km S of this epicenter
- 7.6101 km SE of Sarangani, PhilippinesDecember 16, 1910 · 136 km SW of this epicenter
- 7.6223 km ESE of Sarangani, PhilippinesJanuary 30, 1969 · 123 km SE of this epicenter
- 7.5210 km SSE of Sarangani, PhilippinesAugust 17, 1912 · 245 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 23 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 · 260 km away
2,806 deathsSevere damage ($5–24M)tsunami
- 1913M7.8
Sangihe Island
14 Mar 1913 · 79 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
- 1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 202 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
- 1870
Mindanao: Davao,Blanco
4 Nov 1870 · 217 km away
4 deathsModerate damage ($1–5M)
- 1924M8.3
E Mindanao: Mati,Suriga
14 Apr 1924 · 103 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1903M7.8
Davao Gulf
28 Dec 1903 · 176 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.