Conceptual Geophysical Model of the Berlin Geothermal Field, El Salvador

Abstract

The results of the geophysical studies carried out in the Berlin geothermal field delineate an extensive geothermal field of 15 Km2 at depth. This extends from the south limits of the Berlin caldera and gradually narrowing towards the Northern part of the field.

Two probable upflow zones have been determined by MT and direct current (VES). The first one is located near to the south limit of the Berlin caldera. The second one, which is located near to TR-5 well, is supported by highest temperatures and lowest resistivities measurements.

A good correlation between the results of resistivities survey and borehole data have been observed at the southern part of the wellfield. This suggests equilibrium between the hydrothermal alteration and the temperature, as well as a cooling process in the northern part of the field.

A qualitative and 2.5D quantitative interpretations of the gravity data, yield some evidence about an asymmetrical graben in the Berlin geothermal field. The results do not show any evidence supporting an edge North of the Berlin caldera.