Physics
Scientific paper
Feb 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997pepi..104..127r&link_type=abstract
Physics of the Earth and Planetary Interiors, v. 104, p. 127-146.
Physics
9
Scientific paper
High-frequency coda signals consistently recorded by a temporary seismic network of 29 short-period stations during a 6-month survey in the French Massif Central are concordant with independent evidence for a heterogeneous lower crust obtained from wide-angle and near-vertical reflection experiments in the same region. The teleseismic recordings of 22 events have been analysed in record sections rather than as single station seismograms. Following the low-frequency (LF; 0.5-1.5 Hz) first P-arrival a high-frequency (HF) coda (2-4 Hz dominant frequency) extends over several seconds duration. The HF signals become clearly visible after bandpass filtering, but can also be identified in the original seismograms. In event sections the HF coda forms a consistent pattern of reverberations which is characterized by the following properties: (1) the duration is typically longer on the radial (4-15 s) than on the vertical (3-11 s) component; (2) the beginning of the HF coda, referred to the picked LF first P-arrivals varies between 0-2.5 s, with a dominance around 1.5-2 s; (3) the amplitude of the HF coda is about 3%-10% of the primary LF P-phase amplitude; (4) the signals are incoherent between neighbouring stations and over the network; (5) the HF coda arrives dominantly around the plane of incidence of the teleseismic wave in the first 2 s to maximum 4 s; afterwards a widening of the particle motion to an elliptical shape is observed, indicating arrivals off the sagittal plane. The data parameters (1) to (5) point to the conclusion that the HF signals are generated by a scattering process. Wide-angle and CDP-reflection experiments in the same region measured a similar reverberating coda pattern and located the origin also in the lower crust. These observations and the data parameters of the HF coda suggest that the HF teleseismic waves are scattered at heterogeneities in the lower crust in the Massif Central. In this contribution we mainly concentrate on the presentation of the teleseismic recordings and conclude with a preliminary structural model which contains randomly distributed scatterers in the lower crust.
Fuchs Karl
Mai Martin P.
Ritter Joachim R. R.
Stoll Gerald
No associations
LandOfFree
Scattering of teleseismic waves in the lower crust Observations in the Massif Central, France does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Scattering of teleseismic waves in the lower crust Observations in the Massif Central, France, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Scattering of teleseismic waves in the lower crust Observations in the Massif Central, France will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1607326