Azimuth and slowness anomalies of seismic waves measured on the central California seismographic array. Part II. Interpretation
- 1 June 1966
- journal article
- Published by Seismological Society of America (SSA) in Bulletin of the Seismological Society of America
- Vol. 56 (3), 655-675
- https://doi.org/10.1785/bssa0560030655
Abstract
An interpretation is given here of the azimuth and slowness anomalies for P waves measured on the seven northern stations in the telemetry seismographic array in central California which was described in Part I of this paper. The array provides a new method of investigating the structure of the upper mantle in an important oceanic-to-continental transition region. The structural feature which is primarily responsible for these anomalies is apparently located in the upper mantle within a depth of order 100 km of the surface. Examination shows that if these anomalies are attributed to a thickening crust alone, a dip of the Mohorovičić discontinuity as steep as 20° must be assumed. Further analysis suggests a solution having a moderately dipping Mohorovičić discontinuity below which a second, deeper interface has a velocity decrease downward and a steep dip toward the ocean. An alternative hypothesis to that of Press and Biehler is formulated which explains traveltime anomalies of certain California stations in terms of a regional structural trend.Keywords
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