HR: 0800h
AN: GP21A-03    [Abstracts]
TI: Ultrasensitive Geomagnetic Field Temporal Variations and its Relationship to Stress in the Earth's Crust: an Experiment in the Oaxaca Coast, Mexico.
AU: * Hernandez, J
EM: estebanh@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos s/n Ciudad Universitaria, Mexico, DF 04510, Mexico
AU: Cifuentes-Nava, G
EM: gercifue@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos s/n Ciudad Universitaria, Mexico, DF 04510, Mexico
AU: Cabral-Cano, E
EM: ecabral@Cabral-Cano
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos s/n Ciudad Universitaria, Mexico, DF 04510, Mexico
AU: Hrvoic, I
EM: ivan@gemsys.ca
AF: GEM Systems, 52 West Beaver Creek Road, Suite 14, Richmond Hill, Ont L4B 1L9, Canada
AU: Lopez, F
EM: francisco.lopez@gemsys.ca
AF: GEM Systems, 52 West Beaver Creek Road, Suite 14, Richmond Hill, Ont L4B 1L9, Canada
AU: Wilson, M
EM: mike.wilson@gemsys.ca
AF: GEM Systems, 52 West Beaver Creek Road, Suite 14, Richmond Hill, Ont L4B 1L9, Canada
AB: We present the different assignments developed since June 2004 designed to set up an ultrasensitive magnetometer (Supergrad) built by GEM Systems (Canada). Several geomagnetic surveys, micro-surveys, regional profiles, and Declination-Inclination absolute measurements were carried out, as well as magnetic diurnal variation recording during these tasks. The objective was to reveal areas with a stable magnetic anisotropy inside the site of at least a 200m X 400m area, in order to install three supergradiometer's high sensitivity potassium sensors. This project is undergoing in one of the most seismogenic areas in Mexico: El Trapiche, San Francisco Cozoaltepec, in Santa Maria Tonameca municipality (state of Oaxaca). Different methods of measurement are assessed and a short base gradient method explained. Supersensitive (50fT), potassium 3 sensor gradiometer is described and some field data presented. In the up-to-date significant investments in Earthquake studies and especially in detection of Earthquake precursors there is a lot of emotional and in general non-critical measurements of precursors. We are trying to establish some kind of reference conditions for detection of precursors. For this purpose we are supported by the Supergrad resolution (0.001 pT) and sampling rate (20 Hz). At the same time, a Geomagnetic data-base will be achieved in order to examine the relationship between Earth crust stress and its influence in local geomagnetic field.
UR: http:www.geofisica.unam.mx
DE: 1555 Time variations: diurnal to decadal
DE: 1599 General or miscellaneous
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly