CERRO NEGRO VOLCANO ROGUE ROBOT MAPPING OF PETROLEUM STORAGE RESERVOIR Transient electromagnetic (TEM) methods were applied to an investigation of the subsurface near the August 1999 volcanism at Cerro Negro volcano, Nicaragua. Specifically, the high temperature zones beneath the new vents and their relationship to an earth fissure extending for at least 2 kilometers away from the vents is of interest. Thermal and electrical properties are related based on the variation in electrical resistivity of basalt with temperature. Dry, or moderately dry cool basalt has an almost infinite resistivity, while basalt greater than 600 degrees C is conductive.   The TEM method consists of generating a time-varying magnetic field through the subsurface by abruptly terminating a steady-state current in a wire loop on the ground surface. A secondary magnetic field induced in subsurface conductors is detected at a receiver coil at a specified location on the earth’s surface. It is through a mapping of this secondary magnetic field that the resistivity and geometry of subsurface conductors, or regions of high-temperature basalt, are determined.   The TEM survey at Cerro Negro volcano occurred over three days, from August 21-23, 1999.
	Home | Services | Projects | Publications | Inversion Software | Professional Staff | Contact Us Copyright © 2001 Geophysical Solutions Design by Zango Creative