Chile 8.8 Megaquake Strikes Offshore Maule

Large Earthquake Measuring 8.8Mw Strike Off the Coast of Central Chile

The Chilean Megaquake with nearly 1 exajoule of energy (about 240 megaton, or 16,000 times the size of Hiroshima A-bomb) has caused much destruction

The massive quake struck about 100 km (60 miles) NNW of Chillan, Chile, at a depth of about 35km on February 27, 2010 at 06:34:14 UTC, USGS/EHP reported.

The mainshock was followed by at least 11 medium to powerful aftershocks, as of posting, the largest of which was a magnitude 7.0 shock.

Fatalities/Damage:

According to a local report at least 50 people have been killed, but more deaths are highly probable as the mega earthquake unleashed massive energy. Many buildings have been destroyed. The power lines are  down and communication links between the epicenter and Chilean capital Santiago are affected.

Tsunami Warning:

The Pacific Tsunami Warning Center has issued a tsunami warning for Chile and Peru, and a tsunami watch for Ecuador, Colombia, Panama and Costa Rica.

10-degree Map Centered at 35°S,75°W

Earthquake location Map. Source: USGS/EHP. Enhanced by FEWW

Earthquake Details

• Magnitude: 8.8
• Date-Time:
  • Saturday, February 27, 2010 at 06:34:14 UTC
  • Saturday, February 27, 2010 at 03:34:14 AM at epicenter
• Location: 35.846°S, 72.719°W
• Depth: 35 km (21.7 miles)
• Region: OFFSHORE MAULE, CHILE
• Distances:
  • 100 km (60 miles) NNW of Chillan, Chile
  • 105 km (65 miles) WSW of Talca, Chile
  • 115 km (70 miles) NNE of Concepcion, Chile
  • 325 km (200 miles) SW of SANTIAGO, Chile
• Location Uncertainty: horizontal +/- 7.2 km (4.5 miles)
• Source: USGS NEIC (WDCS-D)
• Event ID:  us2010tfan

Political Map of Chile. Click to enlarge.

Tectonic Summary

This earthquake occurred at the boundary between the Nazca and South American tectonic plates. The two plates are converging at a rate of 80 mm per year. The earthquake occurred as thrust-faulting on the interface between the two plates, with the Nazca plate moving down and landward below the South American plate. Coastal Chile has a history of very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. The February 27 shock originated about 230 km north of the source region of the magnitude 9.5 earthquake of May, 1960 – the largest instrumentally recorded earthquake in the world. This great earthquake killed 1,655 people in southern Chile and unleashed a tsunami that crossed the Pacific, killing 61 people in Hawaii, Japan, and the Philippines. Approximately 870 km to the north of the February 27 earthquake is the source region of the magnitude 8.5 earthquake of November, 1922. This great quake significantly impacted central Chile, killing several hundred people and causing severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii. The magnitude 8.8 earthquake of February 27, 2010 ruptured the portion of the South American subduction zone separating these two massive historical earthquakes. A large vigorous aftershock sequence can be expected from this earthquake. (Source: USGS)

10-degree Map Centered at 35°S,75°W – UPDATE

Earthquake location Map. Source: USGS/EHP. Enhanced by FEWW

Historic Seismicity (USGS/EHP)

Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green

Seismic Hazard Map

Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green

Population Exposure Maps (USGS)

USGS Population Exposure MAP. Click image to enlarge. Click here for PDF version.

USGS Population ShakeMAP. Click image to enlarge.

Other Events:

Meanwhile, GFZ Potsdam – Earthquake Bulletin reported a magnitude 5.8 earthquake in San Juan Province, Argentina, about 600 km NNE of the Chile quake:

Region: San Juan Province, Argentina
Time: 2010-02-27 06:51:19.4 UTC
Magnitude: 5.8
Epicenter: 68.82°W 31.46°S
Depth: 64 km
Status: manually revised

Fire-Earth Earthquake Forecast:  Up to 4 more megaquakes could occur globally in 2010 with probabilities of 0.8 (78%) descending to 0.5 (48%).

[Note: The frequency of occurrence of earthquakes measuring 8.0 Mw or greater is about 1 event per year.]

Related Links:

• Earth undergoing significant geophysical disturbances
• Recent Earthquakes ≥ 6.0 Mw
• Powerful Quake Strikes Chile [November 13, 2009]
• The Largest Earthquake