Reviewed by USGSPhilippines115y ago
M6.4 earthquake 21 km E of Union, Philippines
Thursday, April 24, 1913, 12:15:27 UTC · 9.737°N, 126.309°E
A magnitude 6.4 earthquake struck 21 km E of Union, Philippines on Thursday, April 24, 1913, 12:15:27 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.6 on April 24, 1913.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 15 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
67 kilotons of TNT
That is about 4 times the Hiroshima bomb. It released about 140 times the energy of a magnitude 5.0.
Tectonic setting
45 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
15 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 lists 3 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M7.2 on April 25, 1913. 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 9 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.774 km ENE of Barcelona, PhilippinesJuly 12, 1911 · 160 km SE of this epicenter
- 7.15 km N of Capoocan, PhilippinesMarch 5, 1908 · 255 km NW of this epicenter
- 7.110 km W of Bigaan, PhilippinesJuly 20, 1907 · 159 km S of this epicenter
- 6.616 km E of Cagdianao, PhilippinesApril 24, 1913 · 57 km W of this epicenter
- 6.640 km ENE of Cortes, PhilippinesApril 18, 1913 · 38 km SE of this epicenter
- 6.642 km E of Aras-asan, PhilippinesOctober 10, 1906 · 110 km SE of this epicenter
- 6.475 km ENE of Sulangan, PhilippinesMay 20, 1907 · 152 km N of this epicenter
- 6.34 km SSE of Binucayan, PhilippinesApril 18, 1913 · 182 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1879
Nw Mindanao: Surigao
30 Jun 1879 · 89 km away · intensity X
Extreme damage ($25M+)
- 1911M7.8
Mindanao: Talacogon,Davao,Butuan
12 Jul 1911 · 89 km away · intensity X
Severe damage ($5–24M)tsunami
- 1743
Leyte
Sep 1743 · 273 km away
Severe damage ($5–24M)
- 1871
Camiguin Island: Mambajao,Catarman
20 Feb 1871 · 189 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1885
E Mindanao: Surigao
22 Feb 1885 · 89 km away · intensity VIII
Severe damage ($5–24M)
- 1897M8.1
Northern Samar
18 Oct 1897 · 254 km away · intensity IX
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.