SUBDUCTION GEOMETRY IN CENTRAL PERU FROM A MICROSEISMICITY SURVEY - 1ST RESULTS

Preliminary results from a seismic survey done over the coastal region of Central Peru from April 7 to May 22, 1986 and from previous surveys (1980, 1985) are Presented. The synthesis of these three data sets Permits an accurate study of Central Peru, starting from the coast, across the Altiplano and into the Subandean region. The Wadati-Benioff zone is geometrically well constrained. Subduction near the trench dips at 30-degrees down to a depth of 100 km and then it changes to subhorizontal. Seismicity is noticeable below the western zone but is scarce beneath the Altiplano. Crustal activity in the Subandean region is clearly established.