Reviewed by USGSIndonesia35y ago
M5.4 earthquake 61 km N of Gorontalo, Indonesia
Friday, June 21, 1991, 16:17:29 UTC · 1.093°N, 123.045°E
A magnitude 5.4 earthquake struck 61 km N of Gorontalo, Indonesia on Friday, June 21, 1991, 16:17:29 UTC, at a depth of 30.0 km (shallow). It is the strongest earthquake within 300 km since an M5.4 on June 21, 1991.
- Magnitude
- 5.4
- Moderate · mw
- Depth
- 30 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
2 kilotons of TNT
That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
61 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
30 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 75 km
USGS lists 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.0 on July 11, 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 556 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11939 Sulawesi EarthquakeDecember 21, 1939 · 127 km S of this epicenter
- 7.8160 km W of Gorontalo, IndonesiaJanuary 22, 1905 · 167 km W of this epicenter
- 7.875 km NNW of Gorontalo, IndonesiaApril 18, 1990 · 23 km NW of this epicenter
- 7.579 km NNW of Gorontalo, IndonesiaJune 20, 1991 · 31 km W of this epicenter
- 7.433 km NW of Gorontalo, IndonesiaNovember 8, 1941 · 47 km SW of this epicenter
- 7.491 km SW of Gorontalo, IndonesiaAugust 6, 1984 · 144 km SW of this epicenter
- 7.3108 km SE of Tondano, IndonesiaMay 5, 1908 · 279 km E of this epicenter
- 7.2295 km SSE of Tabiauan, PhilippinesMarch 29, 1907 · 284 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 19 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 123 recorded deaths. The most severe:
- 1845M7.0
N Sulawesi: Menado, Tikala, Tomohon
8 Feb 1845 · 205 km away · intensity IX
118 deathsModerate damage ($1–5M)tsunami
- 1990M7.6
Minahassa Peninsula: Bolaang-Gorontalo
18 Apr 1990 · 23 km away
3 deathsSevere damage ($5–24M)
- 1983M6.1
Central Sulawesi
25 Oct 1983 · 243 km away · intensity VII
2 deathsModerate damage ($1–5M)
- 1991M7.5
Minahassa: Gorontalo, Mamado
20 Jun 1991 · 31 km away · intensity VI
Severe damage ($5–24M)
- 1939M8.0
Centrtal Sulawesi: Kalo,Luwuk,Sula I
21 Dec 1939 · 122 km away
Moderate damage ($1–5M)tsunami
- 1859M7.3
Sulawesi
29 Jul 1859 · 298 km away
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.