Reviewed by USGSTimor Leste35y ago
M4.0 earthquake 86 km WNW of Maubara, Timor Leste
Friday, July 5, 1991, 10:09:56 UTC · 8.270°S, 124.495°E
A magnitude 4.0 earthquake struck 86 km WNW of Maubara, Timor Leste on Friday, July 5, 1991, 10:09:56 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 4.0
- Light · mb
- Depth
- 33 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
15 tons of TNT
That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.
Tectonic setting
60 km
from the nearest mapped plate boundary, between the Banda Sea and Timor plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
33 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 50 km
USGS lists 6 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.3 on July 5, 1991. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.787 km N of Pante Makasar, Timor Leste35y ago · 17 km SW of this epicenter
- 4.876 km NW of Maubara, Timor Leste35y ago · 39 km NE of this epicenter
- 5.295 km N of Pante Makasar, Timor Leste35y ago · 19 km SW of this epicenter
- 4.774 km NNW of Maubara, Timor Leste35y ago · 49 km NE of this epicenter
- 5.390 km NW of Maubara, Timor Leste35y ago · 43 km NE of this epicenter
- 4.654 km NW of Maubara, Timor Leste35y ago · 34 km E of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 266 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.2187 km N of Baukau, Timor LesteFebruary 11, 1969 · 283 km NE of this epicenter
- 7.270 km SE of Maumere, IndonesiaOctober 20, 1938 · 211 km SW of this epicenter
- 7.077 km N of Baukau, Timor LesteFebruary 14, 1952 · 227 km E of this epicenter
- 7.0194 km SE of Baubau, IndonesiaAugust 6, 1914 · 199 km N of this epicenter
- 7.0166 km NNW of Maubara, Timor LesteJune 22, 1966 · 115 km N of this epicenter
- 6.9215 km NW of Maubara, Timor LesteOctober 18, 1964 · 138 km NW of this epicenter
- 6.981 km NW of Maubara, Timor LesteJuly 4, 1991 · 28 km NE of this epicenter
- 6.9160 km NNE of Maumere, IndonesiaJune 7, 1991 · 247 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 418 recorded deaths. The most severe:
- 1896
Timor: Alor Island
18 Apr 1896 · 28 km away · intensity VIII
250 deathsModerate damage ($1–5M)
- 1987M6.5
Timor: Pantar, Mount Sirung
26 Nov 1987 · 38 km away
125 deaths$5 million damagetsunami
- 1991M6.5
Timor: Kalabahi, Dili
4 Jul 1991 · 28 km away
28 deaths$8 million damage
- 1982M5.9
Flores Island: Eastern
25 Dec 1982 · 156 km away
13 deaths$1 million damagetsunami
- 1961M6.5
Flores: Endeh
16 Mar 1961 · 275 km away · intensity VIII
2 deathsModerate damage ($1–5M)
- 1814
Timor Island, Kupang, Kissar Island
1814 · 236 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.