Reviewed by USGSPhilippines99y ago
M7.4 earthquake 10 km ESE of Basak, Philippines
Wednesday, December 19, 1928, 11:37:19 UTC · 6.707°N, 124.245°E
A magnitude 7.4 earthquake struck 10 km ESE of Basak, Philippines on Wednesday, December 19, 1928, 11:37:19 UTC, at a depth of 25.0 km (shallow). It is the strongest earthquake within 300 km since an M8.1 on April 14, 1924.
- Magnitude
- 7.4
- Major · mw
- Depth
- 25 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VII
- Very strong (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
2.0 megatons of TNT
That is about 135 times the Hiroshima bomb. It released about 4,266 times the energy of a magnitude 5.0.
Tectonic setting
331 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
25 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 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.8 on December 28, 1928. 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 41 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 · 133 km S of this epicenter
- 8.11924 Mindanao, Philippines EarthquakeApril 14, 1924 · 212 km E of this epicenter
- 7.947 km ESE of Kalbay, PhilippinesMarch 14, 1913 · 223 km SE of this epicenter
- 7.6101 km SE of Sarangani, PhilippinesDecember 16, 1910 · 300 km SE of this epicenter
- 7.222 km ESE of Bobon, PhilippinesJanuary 1, 1919 · 252 km E of this epicenter
- 7.25 km NW of Kadingilan, PhilippinesMarch 2, 1923 · 125 km NE of this epicenter
- 7.110 km W of Bigaan, PhilippinesJuly 20, 1907 · 279 km NE of this epicenter
- 7.019 km W of Sigaboy, PhilippinesNovember 16, 1927 · 183 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 26 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 311 recorded deaths. The most severe:
- 1913M7.8
Sangihe Island
14 Mar 1913 · 256 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
- 1928M7.4
Cotabato,N Coast Of Illana Bay
19 Dec 1928 · 0 km away · intensity VII
97 deathsModerate damage ($1–5M)tsunami
- 1918M8.3
Mindanao: Cotabato
15 Aug 1918 · 133 km away · intensity X
52 deathsSevere damage ($5–24M)tsunami
- 1897M8.7
Mindanao, Zamboanga, Sulu, Isabela
21 Sep 1897 · 260 km away · intensity IX
13 deathsSevere damage ($5–24M)tsunami
- 1917M6.4
S Mindanao: Glan,Glan Padidu,Tuyan
31 Jan 1917 · 115 km away · intensity IX
7 deathsModerate damage ($1–5M)tsunami
- 1870
Mindanao: Davao,Blanco
4 Nov 1870 · 132 km away
4 deathsModerate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.