Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 1, 1997 | Published
Journal Article Open

Complex scattering within D" observed on the very dense Los Angeles Region Seismic Experiment passive array

  • 1. ROR icon California Institute of Technology


Several seismic phases that scattered within a few hundred kilometers of the base of the mantle are observed in a very dense seismic section. The Los Angeles Region Seismic Experiment passive phase array was composed of 88 seismometers placed along a 175 km profile. Records from two deep earthquakes in Tonga and one earthquake near Honshu, Japan show a secondary arrival between clear P and PcP arrivals. Modeling with layered structures shows that the Tonga and Honshu seismic sections are consistent with an increase in seismic velocity 140 and 240 km above the core-mantle boundary, respectively, and a ≃10-km thick low-velocity zone at the base of the mantle beneath a region in the mid Pacific. Several of these arrivals are not coherent enough to appear in higher resolution stacks from the much larger Southern California Seismic Network. This experiment illustrates that fine-scale passive array data can reveal small-scale deep Earth structure invisible to larger-scale seismic networks.

Additional Information

© 1997 American Geophysical Union. 

Attached Files

Published - Kohler_et_al-1997-Geophysical_Research_Letters.pdf


LARSE93 was a joint effort involving scientists from the University of California at Los Angeles, the U. S. Geological Survey, the California Institute of Technology, and the University of Southern California. Our appreciation goes to Ed Garnero for providing the generalized rays synthetic seismogram code. The manuscript was greatly strengthened by comments from Michael Weber and Don Helmberger. This work was funded by the Southern California Earthquake Center (contribution number 353) and by National Science Foundation grant EAR 96-28051.


Files (602.1 kB)

Additional details

August 19, 2023
March 13, 2024