Reviewed by USGSChile28y ago
M4.2 earthquake 132 km WSW of Illapel, Chile
Wednesday, February 3, 1999, 22:34:17 UTC · 31.880°S, 72.539°W
A magnitude 4.2 earthquake struck 132 km WSW of Illapel, Chile on Wednesday, February 3, 1999, 22:34:17 UTC, at a depth of 25.5 km (shallow).
- Magnitude
- 4.2
- Light · md
- Depth
- 26 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
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
17 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
26 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.9 on March 4, 1999. 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 442 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 · 122 km SE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 130 km NE of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 153 km SE of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 153 km SE of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 144 km SE of this epicenter
- 7.419 km S of Valparaíso, ChileMarch 4, 1985 · 169 km SE of this epicenter
- 7.237 km S of San Antonio, ChileMarch 18, 1931 · 245 km S of this epicenter
- 7.259 km S of San Antonio, ChileApril 9, 1985 · 265 km S 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 4,768 recorded deaths. The most severe:
- 1906M8.2
South Central
17 Aug 1906 · 134 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 139 km away
400 deaths$125 million damage
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 160 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
- 1971M7.8
Central
9 Jul 1971 · 144 km away · intensity IX
83 deaths$236 million damagetsunami
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 134 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
- 1943M8.2
Illapel
6 Apr 1943 · 136 km away
11 deathsLimited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.