HR: 1340h
AN: S33B-0319    [Abstracts]
TI: Comparison of Tilt Data With Long Period Seismograms: Surface Waves and Earth Free Oscillations
AU: Oreye, N F
EM: nicolas.doreye@ecgs.lu
AF: Natural History Museum of Luxembourg and European Center for Geodynamics and Seismology, 19 Rue Josy Welter, Walferdange, 7256 Luxembourg
AU: * Ferreira, A M
EM: anaf@earth.ox.ac.uk
AF: Department of Earth Sciences, University of Oxford, Parks Road , Oxford, OX1 3PR United Kingdom
AU: Woodhouse, J H
EM: John.Woodhouse@earth.ox.ac.uk
AF: Department of Earth Sciences, University of Oxford, Parks Road , Oxford, OX1 3PR United Kingdom
AU: Zuern, W
EM: walter.zuern@gpi.uni-karlsruhe.de
AF: Black Forest Observatory, Schiltach and University of Karlsruhe, Karlsruhe, 1000 Germany
AB: We compare observations of long period seismic surface waves and free oscillations recorded by a high resolution long base water-tube tiltmeter and by nearby broadband seismometers after large earthquakes. The quality of the tiltmeter data is comparable to that of the best seismic data, recording some of the gravest seismic free oscillations, as well as successive passages of seismic surface waves circling the globe. We compare the observations with theoretical seismograms and with theoretical tilt. The predicted and observed surface wave tilt waveforms are very similar provided that we take into account both pure tilt and horizontal acceleration effects on the tiltmeter. Phase and amplitude anomalies between the waveforms are very well explained by the theoretical transfer function of the instrument. Likewise, observed horizontal seismograms converted into tilt match the tiltmeter data very well. Since the water-tube tiltmeter has very low cost and easy installation, potentially it could have an important contribution to long period seismology.
DE: 1294 Instruments and techniques
DE: 7255 Surface waves and free oscillations
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005