HR: 1400h
AN: V23A-16    [Abstracts]
TI: Comparative Spectrograms Between the Popocatepetl Volcano Magnetic Station and the Teoloyucan Magnetic Observatory, Mexico.
AU: * Cifuentes-Nava, G
EM: gercifue@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos S/N Cd. Universitaria, Mexico, DF 04510, Mexico
AU: Hernandez-Quintero, J E
EM: estebanh@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos S/N Cd. Universitaria, Mexico, DF 04510, Mexico
AU: Cabral-Cano, E
EM: ecabral@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos S/N Cd. Universitaria, Mexico, DF 04510, Mexico
AU: Martin-Del Pozzo, A L
EM: analil@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos S/N Cd. Universitaria, Mexico, DF 04510, Mexico
AU: Chavez-Segura, R E
EM: exprene@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Circuito Institutos S/N Cd. Universitaria, Mexico, DF 04510, Mexico
AB: We present a comparative spectrogram analysis for the Popocatepetl Volcano magnetic station (70.943° N CoLat, 261.363° E, 4029 m) and the Teoloyucan Magnetic Observatory (70.254° N CoLat, 260.807º E, 2280 m) time series between 1997 and 2003. Instrumentation at both sites include a Geometrics G856 proton-precession magnetometer operating at a 60 second sampling rate and is complemented with the magnetic record from a dF fluxgate variograph at the Teoloyucan Magnetic Observatory (TEO). Popocatepetl's total magnetic field record is reconstructed using a harmonic analysis technique, and subtracted to the TEO record, which is considered as a reference site. The resulting difference shows a significant diurnal component, presumably from a local magnetic induction or from ionospheric origin. This is in sharp contrast with our initial considerations for geomagnetic volcano monitoring that considered the distance between both sites to be close enough and assumed similar ionospheric conditions at both sites. This diurnal component influence can be removed using a normalized difference approach or by cancellation during the harmonic reconstruction process. This analysis will improve previously used techniques such as normalized differences or correlation in magnetic data analysis for short, middle and long term active volcano magnetic monitoring.
DE: 8419 Volcano monitoring (7280)
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly