[1] A 400-km-long seismic reflection profile (Andean Continental Research Project 1996 (ANCORP'96)) and integrated geophysical experiments (wide-angle seismology, passive seismology, gravity, and magnetotelluric depth sounding) across the central Andes (21°S) observed subduction of the Nazca plate under the South American continent. An east dipping reflector (Nazca Reflector) is linked to the down going oceanic crust and shows increasing downdip intensity before gradual breakdown below 80 km. We interpret parts of the Nazca Reflector as a fluid trap located at the front of recent hydration and shearing of the mantle, the fluids being supplied by dehydration of the oceanic plate. Patches of bright (Quebrada Blanca Bright Spot) to more diffuse reflectivity underlie the plateau domain at 15-30 km depth. This reflectivity is associated with a low-velocity zone, P to S wave conversions, the upper limits of high conductivity and high V p /V s ratios, and to the occurrence of Neogene volcanic rocks at surface. We interpret this feature as evidence of widespread partial melting of the plateau crust causing decoupling of the upper and lower crust during Neogene shortening and plateau growth. The imaging properties of the continental Moho beneath the Andes indicate a broad transitional character of the crust-mantle boundary owing to active processes like hydration of mantle rocks (in the cooler parts of the plate margin system), magmatic underplating and intraplating under and into the lowermost crust, mechanical instability at Moho, etc. Hence all first-order features appear to be related to fluid-assisted processes in a subduction setting.

Seismic technology advances and well established reservoir workflow industry practices have led to a more accurate description of subsurface through reservoir models. Seismic driven reservoir characterization is a dynamic process in which iterative calibration and interpretation of information contributes to geologically sound and quantitatively calibrated model. Whether the main goal of the reservoir characterization is structural or stratigraphic, or even a quantitative reservoir property calculation and distribution, it is essential to focus efforts that contribute to: (1) the quality of the input data; (2) the best acquisition/processing methods and, (3) the calibration and correction of seismic-well log data that contribute in lowering uncertainties.This presentation deals with the cons and pros in using seismic as main driver while building reservoir models. Three cases are presented Case 1: Seismic reservoir architecture of prograding events in a falling seal level stage.

Las construcciones civiles edificadas sobre suelos inestables son vulnerables a los procesos naturales como la geodinámica interna, externa y el cambio climático. El poblado de Tapacocha que está asentado sobre suelo deslizado es sensible a los procesos naturales. El terremoto de mayo de 1970 ocasionó fracturamiento de la planicie, destrucción de sus construcciones; las intensas lluvias de los años 1942 y 1997 ocasionaron huaycos que destruyeron algunas de sus edificaciones y terrenos de cultivo. La geodinámica interna modeló el basamento con un intenso plegamiento y fracturamiento de las rocas sedimentarias; la geodinámica externa por geoformas modeladas por los movimientos rotacionales, deslizamientos, erosión diferencial. En la actualidad el efecto del cambio climático se manifiestan por las inusuales torrenciales lluvias que erosionan periódicamente y ponen en peligro las edificaciones civiles y la agricultura. Con el presente estudio se propone alertar a las autoridades y sus pobladores para prevenir y mitigar los efectos naturales destructivos. Palabras clave.- poblado de Tapacocha, geodinámica externa, huaycos. ABSTRACT Buildings standing on unstable soils are vulnerable to natural processes such as internal and external geodynamics and climate change. The village of Tapacocha, which is settled on slid floor, would be sensitive to those natural processes. The May 1970 earthquake caused ground fracture and building destruction; heavy rains in 1942 and 1997 caused mudslides that destroyed buildings and agriculture land. The internal geodynamics gave its shape to the base rocks through intense folding and fracturing of the sedimentary rocks; the external geodynamics created shapes through rotational movements, landslides and differential erosion. Presently, climate change is causing unusual torrential rains that periodically erode and threaten buildings and agriculture. The goal of this study is to advise the authorities and the population on ways to prevent and mitigate the destructive effects of these natural events. Keywords.- village of Tapacocha, external geodynamics, mudslides.

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