Sunday, 12 January 2014

Back in Chile

A year on from our last field season, and we’re back in Chile continuing our search for evidence of earthquakes and tsunamis. So far we’ve visited two new sites – Pucatrihue (west of Osorno) and Llico (3 hours further south). We are working on the salt marshes at these sites and are interested in the sequence of sediments which have accumulated in the marshes over time. As the environment (or elevation of the land relative to the sea) changes, the nature of the sediment which is deposited changes. We’re particularly interested in where we find a very sudden or sharp change in sediments; where we see the
same sharp change at lots of points across the marsh, this can indicate there has been an earthquake event causing a rapid change in elevation and hence sedimentary environment. Often there will also be a layer of sand at the sharp sediment boundary, deposited during the tsunami generated by the earthquake. We investigate the sediment history at these sites by using a corer to drill a hole into the ground (normally 1.5 – 3 m deep). So far the sediments are looking very interesting and we’ve already sampled a lot to take back to analyse in the labs.

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