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.



Monday, 16 August 2010

Bucalemu, Boyeruca and Llico

We’ve started the trip towards the northern end of the 2010 rupture zone, driving though the vineyards of the Colchagua Valley from Santiago to our first base at Laguna Torca, close to the village of Llico. The coastal villages in this area have been badly affected by the tsunami, with about half the population living in government issue temporary housing.

We were hoping that water levels in the estuaries at Bucalemu, Boyeruca (left) and Llico would respond to relative sea-level change, however all three have been separated from the sea by sand bars. Water levels in the lagoons behind changed with the breaching of the bars by the tsunami and also change when the bars are artificially cut (sometimes with dynamite) when winter river floods inundate farmland. A recent Science paper does, however, suggest the area may have coseismically subsided in February.

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