Sequel of aftershocks hit O'Higgins, Bíobío and Maule regions in Chile

Aftershock earthquake location.
Image: United States Geological Survey.

The Church of Santa Cruz, after the 8.8 February earthquake.
Image: Diego Grez.

Thursday, March 25, 2010 

Santa Cruz, Chile — An aftershock earthquake that reached a magnitude of 4.9 on the Richter magnitude scale struck Chile yesterday at 11:14 local time (15:14 UTC). The epicentre was in the Maule Region. The aftershock lasted about fifteen or twenty seconds.

According to the ONEMI (National Emergencies Office), it had an intensity of five Mercalli grades in the coastal area of Pelluhue, four in Cauquenes, Chanco, San Javier, and Longaví, and three in Pencahue. The US Geological Survey reported that the epicentre was located in the sea, at a depth of 25,5 kilometers, and 115 kilometers west of Talca.

There were no reports of damage or injuries. Previously, at 08:30 am local time (12:30 UTC), another aftershock reached 5.0 on the Richter scale and was clearly felt in the Bío Bío Region. The epicenter was located at a depth of 35 kilometers, and 55 kilometers northeast from Concepción.

A minor aftershock, with epicentre in Pichilemu, reached a magnitude of 3.6 in the Richter scale at 15:11 local time (19:11 UTC), as reported the University of Chile's Geological Survey.

Damages in Chile surpass the 30.000 million U.S. dollars. The most affected regions by the aftershocks are the Bío Bío Region, Valparaíso, Maule and O'Higgins. Almost 350 aftershocks have been felt in these areas since the February 27 earthquake.

At 23:58 local time (03:58 UTC), a medium intensity aftershock between 2 and 6 grades in the Richter scale occurred, in the Maule, O'Higgins, Valparaíso, and Santiago Metropolitan regions. The epicenter was located near Talca, as ONEMI reported, where the aftershock was felt with more intensity. In Curicó, Río Claro and Yerbas Buenas, it reached 5 grades in the Richter scale; in Parral, Linares, Retiro, and Cauquenes, it reached 3 grades; in Rancagua and San Fernando, 4 grades; in Pichilemu, 2 grades; and in Santiago de Chile and San Antonio, 2 grades. ONEMI has not reported damage or injuries.

Another 4 medium intensity aftershocks took place after Talca's: at 01:17 AM local time (05:17 UTC), reaching 3.9 grades, with epicentre near Constitución; 4.7 grades at 09:59 local time (13:59 UTC), with epicentre near Pichilemu; at the 10:57 local time (14:57 UTC) reaching 5.1 grades, with epicentre almost twenty kilometers at the north of Cobquecura; and a 3.9 grades at the 12:20, with epicentre near Pichilemu.

Sources

• "Sismos afectaron esta mañana al Biobío y el Maule" — La Nación (Chile), March 24, 2010 (Spanish)
• "Fuerte sismo se registró esta mañana en Región del Biobío" — La Tercera, March 24, 2010 (Spanish)
• "Sismo mediana intensidad Región del Maule" — ONEMI, March 24, 2010 (Spanish)
• "5 Talca" — University of Chile's Geological Survey, March 25, 2010 (Spanish)
• "Últimos Sismos Sensibles" — University of Chile's Geological Surve, March 25, 2010 (Spanish)
• "Sismo de mediana intensidad Regiones del Maule, O`Higgins, Valparaíso y Metropolitana" — ONEMI, March 25, 2010 (Spanish)
• "3.6 Pichilemu, Chile 7 km. W" — University of Chile's Geological Survey, March 24, 2010 (Spanish)
• "5,0 Offshore Bíobío, Chile" — USGS, March 24, 2010
• "4,9 Offshore Maule, Chile" — USGS, March 24, 2010