Reviewed by USGSIndonesia35y ago
M5.0 earthquake 255 km NNW of Gorontalo, Indonesia
Wednesday, May 22, 1991, 08:21:27 UTC · 2.647°N, 122.120°E
A magnitude 5.0 earthquake struck 255 km NNW of Gorontalo, Indonesia on Wednesday, May 22, 1991, 08:21:27 UTC, at a depth of 584.6 km (deep). It is the strongest earthquake within 300 km since an M5.9 on May 19, 1991.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 585 km
- Deep
- 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
33 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: deep
585 km
Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.
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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M4.9 on May 24, 1991. 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 253 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 · 233 km S of this epicenter
- 7.875 km NNW of Gorontalo, IndonesiaApril 18, 1990 · 182 km SE of this epicenter
- 7.7228 km SW of Sarangani, PhilippinesJune 11, 1972 · 262 km NE of this epicenter
- 7.433 km NW of Gorontalo, IndonesiaNovember 8, 1941 · 227 km S of this epicenter
- 7.2295 km SSE of Tabiauan, PhilippinesMarch 29, 1907 · 154 km NE of this epicenter
- 7.1156 km NW of Gorontalo, IndonesiaJanuary 11, 1913 · 143 km S of this epicenter
- 7.069 km N of Gorontalo, IndonesiaMay 19, 1991 · 190 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5 recorded deaths. The most severe:
- 1990M7.6
Minahassa Peninsula: Bolaang-Gorontalo
18 Apr 1990 · 182 km away
3 deathsSevere damage ($5–24M)
- 1983M6.1
Central Sulawesi
25 Oct 1983 · 219 km away · intensity VII
2 deathsModerate damage ($1–5M)
- 1991M7.5
Minahassa: Gorontalo, Mamado
20 Jun 1991 · 178 km away · intensity VI
Severe damage ($5–24M)
- 1983M6.0
Celebes: Minahassa: Tolitoli
16 Oct 1983 · 210 km away
Moderate damage ($1–5M)
- 1905M8.4
Minahassa Peninsula
22 Jan 1905 · 208 km away
- 1972M7.8
Celebes Sea
11 Jun 1972 · 279 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.