Publication details
Usage of magnetic studies in coastal paleoseismology, Mexican Pacific coast
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| Year of publication | 2015 |
| Type | Conference abstract |
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| Description | Subduction zone earthquakes can generate abrupt vertical movement of the seafloor or submarine landslide. Both can produce a tsunami wave that can hit coastal areas. Such waves transport material which is usually deposited on flat plains and in topofraphic depressions on the coast. From this point of view, lagoons are ideal environments where tsunami deposits can be preserved. The studied sites were situated in lagoons on the active Mexican continental margin, where both storm and tsunami inundations can occur. Despite the fact that magnetic studies alone can’t help solving the question if the inundation sediment was deposited by a tsunami or storm event, they can significantly help to respond other important questions. Recently, the potential of magnetic proxies in marine inundation deposits studies is still under consideration and there are some methodological difficulties. Our most recent results showed that: 1) magnetic studies may be useful to determine what material was the main source of magnetic minerals in sediments; 2) AMS can help to distinguish different hydrodynamical environments related to different layers; 3) primary sedimentary fabric in fine-grained lagoon sediments such clays may have developed lateral imbrication; 4) the lateral variability of AMS parameters can be significant and a test of horizontal variability in sedimentary beds should be performed before final interpretations; 5) In some specific cases AMS fabrics might help to determine flow direction of the tsunami and this might be a hint if the triggering actor was an earthquake or submarine landslide. |