On 27th February 2010 a magnitude 8.8 earthquake stuck central Chile. The earthquake, the fifth largest instrumentally recorded, caused a moderate tsunami, exceeding 2.3m in Talcahuano, Chile, 1.7m in the Marquesas and 0.9m in Hawai’i. The earthquake and tsunami resulted in over 500 deaths and a financial cost exceeding $20bn.

The earthquake filled a seismic gap, a section of the Chilean subduction zone that had not ruptured since 1835. Significant land level changes accompanied both the 1835 and 2010 earthquakes. We are making a rapid assessment of the sedimentary record associated with the land level changes and tsunami.



Saturday, 21 August 2010

Lipimavida to Rio Mataquito

From Llico we travelled south to Lipimavida, Iloca and the Rio Mataquito. Post-earthquake imagery has been added to Google Earth for the area. Try using the historical imagery tool for the Chilean coastline around 35˚S - the changes are surprisingly evident.

The mouth of the Rio Mataquito is now a kilometre south of its former location, probably as a result of either the tsunami or subsidence. Fishermen at Duao told us that the tides are higher than before the earthquake, supporting coseismic subsidence. We took blocks of sediment from close to the new mouth of the river and will try to quantify the amount of subsidence by analysing the diatoms (single celled algae) they contain.

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