Reviewed by USGSTimor Leste35y ago
M4.6 earthquake 54 km NW of Maubara, Timor Leste
Friday, July 5, 1991, 11:21:56 UTC · 8.339°S, 124.797°E
A magnitude 4.6 earthquake struck 54 km NW of Maubara, Timor Leste on Friday, July 5, 1991, 11:21:56 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on July 4, 1991.
- Magnitude
- 4.6
- 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
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
76 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 4 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.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 270 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 · 262 km NE of this epicenter
- 7.258 km ENE of Lospalos, Timor LesteSeptember 29, 1905 · 294 km E of this epicenter
- 7.270 km SE of Maumere, IndonesiaOctober 20, 1938 · 239 km W of this epicenter
- 7.077 km N of Baukau, Timor LesteFebruary 14, 1952 · 197 km E of this epicenter
- 7.0194 km SE of Baubau, IndonesiaAugust 6, 1914 · 218 km NW of this epicenter
- 7.0166 km NNW of Maubara, Timor LesteJune 22, 1966 · 124 km N of this epicenter
- 6.9215 km NW of Maubara, Timor LesteOctober 18, 1964 · 164 km NW of this epicenter
- 6.981 km NW of Maubara, Timor LesteJuly 4, 1991 · 30 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 416 recorded deaths. The most severe:
- 1896
Timor: Alor Island
18 Apr 1896 · 11 km away · intensity VIII
250 deathsModerate damage ($1–5M)
- 1987M6.5
Timor: Pantar, Mount Sirung
26 Nov 1987 · 71 km away
125 deaths$5 million damagetsunami
- 1991M6.5
Timor: Kalabahi, Dili
4 Jul 1991 · 30 km away
28 deaths$8 million damage
- 1982M5.9
Flores Island: Eastern
25 Dec 1982 · 189 km away
13 deaths$1 million damagetsunami
- 1814
Timor Island, Kupang, Kissar Island
1814 · 245 km away
Severe damage ($5–24M)tsunami
- 1989M6.2
Timor: Alor
14 Jul 1989 · 46 km away
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.