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.



Thursday, 2 September 2010

Tirua

We were woken yesterday morning by the house shaking… According to the USGS (link) a magnitude 4.7 earthquake, with an epicentre 20km east of Lebu was responsible. The excitement continued with the purchase of our third and fourth spades of the trip. If you’re thinking of digging holes in South America, we’d suggest avoiding Brazilian spades.

We’ve spent a couple of days investigating the area around Tirua. Locals told us that the February tsunami travelled 3 or 4 kilometres up the river valley, carrying several houses inland. The tsunami deposited dark grey sand in a layer up to 25cm thick (right). We found further sand layers in exposures along the side of the river that might be evidence for older tsunamis.

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