IAG-IASPEI 2017

講演情報

Oral

Joint Symposia » J05. Crustal dynamics: Multidisciplinary approach to seismogenesis

[J05-1] Crustal dynamics: Multidisciplinary approach to seismogenesis I

2017年8月1日(火) 13:30 〜 15:00 Room 501 (Kobe International Conference Center 5F, Room 501)

Chairs: Takeshi Sagiya (Nagoya University) , Kuo-Fong Ma (National Central University)

13:30 〜 13:45

[J05-1-01] Southern Costa Rica and the Next Decade: A Spatial and Temporal Opportunity for an International Subduction Zone Observatory

Marino Protti, Cyril Muller (Costa Rica Volcanological and Seismological Observatory, Heredia, Costa Rica)

A locked segment of the Middle America Subduction Zone surrounding Osa peninsula in southern Costa Rica has experienced large (Mw=7.2-7.4) earthquakes in 1856, 1904, 1941 and 1983. With an average recurrence interval of roughly 40 years and 34 years since the last rupture, the timing is right to instrument and record data of unrivalled importance before, during and after the next megathrust earthquake in this region.

The subducting young and anomalous (rejuvenated and thickened) lithosphere there, leads to shallow subduction. As a consequence, the plate interface beneath Osa peninsula lies 4 to 8 km beneath land where it is easily accessible for inland drilling. Furthermore, since the trench is only 20-30 km from the SW coastline of Osa peninsula, submarine cables with seafloor instrumentation, power and data transmission could be deployed and tight to borehole instrumentation, at a much lower cost than in other subduction zones.

The Costa Rica Volcanological and Seismological Observatory at Universidad Nacional (OVSICORI-UNA) is taking advantage of this great geographical and temporal opportunity to build and operate a dense geodynamic control network to record a wealth of data of unrivalled importance before, during and after the next megathrust earthquake in this region. With the growing interest for international subduction zone observatories, we invite the scientific community to joint efforts to fully capture the geophysical processes occurring in this subduction zone.