Reviewed by USGSIndonesia58y ago
M5.5 earthquake 74 km N of Palu, Indonesia
Thursday, August 15, 1968, 11:40:33 UTC · 0.241°S, 119.952°E
A magnitude 5.5 earthquake struck 74 km N of Palu, Indonesia on Thursday, August 15, 1968, 11:40:33 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.2 on August 14, 1968.
- Magnitude
- 5.5
- Moderate · 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 earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/5 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.
Tectonic setting
38 km
from the nearest mapped plate boundary, between the Molucca Sea and Banda Sea 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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.7 on August 15, 1968. 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 49 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 · 208 km NE of this epicenter
- 7.7120 km NE of Palu, IndonesiaMay 19, 1938 · 69 km E of this epicenter
- 7.2112 km N of Palu, IndonesiaAugust 14, 1968 · 44 km NW of this epicenter
- 7.1156 km NW of Gorontalo, IndonesiaJanuary 11, 1913 · 284 km NE of this epicenter
- 6.977 km NNW of Masamba, IndonesiaJune 7, 1968 · 185 km S of this epicenter
- 6.8109 km WSW of Luwuk, IndonesiaMarch 17, 1909 · 236 km SE of this epicenter
- 6.747 km WNW of Luwuk, IndonesiaJune 30, 1964 · 279 km E of this epicenter
- 6.799 km W of Gorontalo, IndonesiaMarch 28, 1964 · 258 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 267 recorded deaths. The most severe:
- 1968M7.4
Sulawesi: Tambu,Coast Of Mapaga
14 Aug 1968 · 52 km away · intensity VIII
200 deathsSevere damage ($5–24M)tsunami
- 1927M6.2
Sulawesi: Donggala
1 Dec 1927 · 114 km away · intensity VII
50 deathsSevere damage ($5–24M)tsunami
- 1938M7.7
Sulawesi Island
19 May 1938 · 69 km away · intensity IX
17 deathsSevere damage ($5–24M)tsunami
- 1921M6.2
Sangkulirang,Rending,Kariorang,Sekuran
14 May 1921 · 251 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1907
Sulawesi: Lemo, Colo, Anja, Olu Congko
30 Jul 1907 · 228 km away · intensity VIII
Moderate damage ($1–5M)
- 1960
Central Sulawesi: Una-Una Island
29 Apr 1960 · 175 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.