Reviewed by USGSChile28y ago
M4.3 earthquake 110 km WNW of Illapel, Chile
Sunday, January 31, 1999, 23:20:28 UTC · 31.188°S, 72.208°W
A magnitude 4.3 earthquake struck 110 km WNW of Illapel, Chile on Sunday, January 31, 1999, 23:20:28 UTC, at a depth of 1.1 km (shallow).
- Magnitude
- 4.3
- Light · md
- Depth
- 1 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
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
41 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
1 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 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.2 on February 24, 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 432 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 · 155 km SE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 80 km E of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 219 km S of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 187 km SE of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 175 km SE of this epicenter
- 7.419 km S of Valparaíso, ChileMarch 4, 1985 · 230 km S of this epicenter
- 7.2135 km W of Valparaíso, ChileOctober 16, 1981 · 231 km S of this epicenter
- 7.136 km SW of Monte Patria, ChileOctober 15, 1997 · 98 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 40 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 4,766 recorded deaths. The most severe:
- 1906M8.2
South Central
17 Aug 1906 · 202 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 165 km away
400 deaths$125 million damage
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 221 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
- 1971M7.8
Central
9 Jul 1971 · 174 km away · intensity IX
83 deaths$236 million damagetsunami
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 202 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
- 1943M8.2
Illapel
6 Apr 1943 · 53 km away
11 deathsLimited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.