Reviewed by USGSPhilippines106y ago
M6.5 earthquake 44 km ENE of Anito, Philippines
Saturday, May 21, 1921, 08:42:12 UTC · 12.670°N, 125.635°E
A magnitude 6.5 earthquake struck 44 km ENE of Anito, Philippines on Saturday, May 21, 1921, 08:42:12 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on March 5, 1908.
- Magnitude
- 6.5
- Strong · mw
- Depth
- 35 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
85 kilotons of TNT
That is about 6 times the Hiroshima bomb. It released about 178 times the energy of a magnitude 5.0.
Tectonic setting
15 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
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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.15 km N of Capoocan, PhilippinesMarch 5, 1908 · 183 km SW of this epicenter
- 6.8123 km NE of Cabatuan, PhilippinesDecember 10, 1905 · 89 km N of this epicenter
- 6.475 km ENE of Sulangan, PhilippinesMay 20, 1907 · 200 km SE of this epicenter
- 6.23 km WSW of Irosin, PhilippinesNovember 8, 1912 · 177 km W of this epicenter
- 6.175 km NE of Cabatuan, PhilippinesFebruary 25, 1917 · 35 km N of this epicenter
- 6.024 km WSW of Mabiton, PhilippinesMay 28, 1917 · 281 km W of this epicenter
- 6.027 km NNE of Kaliliog, PhilippinesSeptember 7, 1917 · 295 km NW of this epicenter
- 5.971 km NE of Cabatuan, PhilippinesFebruary 25, 1917 · 37 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 17 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 52 recorded deaths. The most severe:
- 1840M6.5
Sorsogon,Masbate Is,Casiguran,Albay
22 Mar 1840 · 190 km away · intensity IX
52 deathsSevere damage ($5–24M)tsunami
- 1897M7.9
Masbate Island
13 May 1897 · 193 km away · intensity VIII
Severe damage ($5–24M)tsunami
- 1869M7.0
Masbate Island
16 Aug 1869 · 232 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1743
Leyte
Sep 1743 · 219 km away
Severe damage ($5–24M)
- 1814
Se Luzon: Albay
2 Feb 1814 · 194 km away · intensity VII
Severe damage ($5–24M)
- 1897M8.1
Northern Samar
18 Oct 1897 · 84 km away · intensity IX
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.