Reviewed by USGSIndonesia106y ago
M6.5 earthquake 172 km ENE of Bontang, Indonesia
Saturday, May 14, 1921, 11:17:55 UTC · 0.677°N, 118.938°E
A magnitude 6.5 earthquake struck 172 km ENE of Bontang, Indonesia on Saturday, May 14, 1921, 11:17:55 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on January 22, 1905.
- Magnitude
- 6.5
- Strong · mw
- Depth
- 35 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 earthquake
In context
How big was it, and why here?
Energy released
91 kilotons of TNT
That is about 6 times the Hiroshima bomb. It released about 191 times the energy of a magnitude 5.0.
Tectonic setting
35 km
from the nearest mapped plate boundary, between the Molucca 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 5 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8160 km W of Gorontalo, IndonesiaJanuary 22, 1905 · 299 km E of this epicenter
- 6.435 km NNW of Palu, IndonesiaMay 25, 1907 · 170 km SE of this epicenter
- 6.3Sulawesi, IndonesiaJuly 29, 1907 · 232 km SE of this epicenter
- 6.3211 km SE of Tarakan, IndonesiaJune 24, 1907 · 141 km N of this epicenter
- 6.3210 km ESE of Tarakan, IndonesiaMay 19, 1920 · 208 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1921M6.2
Sangkulirang,Rending,Kariorang,Sekuran
14 May 1921 · 115 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1860
Sulawesi: Minahassa
Aug 1860 · 239 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.