Reviewed by USGSChile28y ago
M3.8 earthquake 21 km SSE of San Antonio, Chile
Saturday, November 21, 1998, 14:47:15 UTC · 33.783°S, 71.559°W
A magnitude 3.8 earthquake struck 21 km SSE of San Antonio, Chile on Saturday, November 21, 1998, 14:47:15 UTC, at a depth of 42.0 km (shallow).
- Magnitude
- 3.8
- Minor · md
- Depth
- 42 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
8 tons of TNT
That is about 1/1,992 of the Hiroshima bomb. A magnitude 5.0 releases about 63 times more energy.
Tectonic setting
126 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
42 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 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.0 on December 19, 1998. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.031 km W of San Antonio, Chile28y ago · 41 km NW of this epicenter
- 3.12 km SW of San Antonio, Chile28y ago · 20 km N of this epicenter
- 2.731 km S of Melipilla, Chile28y ago · 37 km SE of this epicenter
- 3.641 km SW of San Antonio, Chile28y ago · 31 km SW of this epicenter
- 3.7Off the coast of Valparaiso, Chile28y ago · 47 km W of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 372 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.2The 1906 Valparaiso, Chile EarthquakeAugust 17, 1906 · 154 km N of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 281 km N of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 78 km N of this epicenter
- 7.826 km WNW of San Carlos, ChileJanuary 25, 1939 · 286 km S of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 135 km N of this epicenter
- 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 159 km SW of this epicenter
- 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 194 km SW of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 145 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 38 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 49,041 recorded deaths. The most severe:
- 1939M8.3
Chillan
25 Jan 1939 · 281 km away · intensity X
30,000 deaths$920 million damagetsunami
- 1861
Mendoza, San Luiz
20 Mar 1861 · 279 km away · intensity IX
14,000 deathsExtreme damage ($25M+)tsunami
- 1906M8.2
South Central
17 Aug 1906 · 96 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 157 km away
400 deaths$125 million damage
- 1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 141 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 74 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.