[1] Univ Austral Chile, Escuela Geol, Fac Ciencias, Valdivia 5090000, Chile
[2] Millennium Nucleus Seism Cycle Subduct Zones, Valdivia, Chile
[3] Univ Austral Chile, Fac Ciencias, Inst Ciencias Tierra, Valdivia 5090000, Chile
[4] Univ York, Dept Environm & Geog, York, England