| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
DALLAS SEISMOLOGICAL OBSERVATORY SOUTHERN METHODIST UNIVERSITY, DALLAS, TEXAS
EARTH SCIENCES LABORATORY ENVIRONMENTAL SCIENCE SERVICE ADMINISTRATION, BOULDER, COLORADO
Abstract
Epicenter determinations using data from stations at distances greater than 20° from the source make use of standard travel times based on a spherically symmetrical Earth. Lateral inhomogeneities in the upper mantle result in relative delays with respect to the standard times. Delays associated with the end of the up-traveling ray can be handled through the use of station corrections. A constant delay beneath the source can not be easily corrected, but it will result only in errors in origin time. However, if the delay arising beneath the source changes with azimuth, a consistent error, here called source bias, will be present in the estimate of the epicenter. Studies of explosions within continental masses have revealed no significant source bias; however, events on two linear, volcanic island chains in the Pacific (Rat Islands-Aleutians and Hawaii) show significant source bias. Errors arising from this effect may be as large as 
degree and are most likely to occur with events near tectonically active island chains.
This article has been cited by other articles:
|
|
 |
|
  A. Douglas, J. B. Young, D. Bowers, and P. D. Marshall An Analysis of P Travel Times for Nevada Test Site Explosions Recorded at Regional Distances Bulletin of the Seismological Society of America, June 1, 2005; 95(3): 941 - 950. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Validation of Regional and Teleseismic Travel-Time Models by Relocating Ground-Truth Events Bulletin of the Seismological Society of America, June 1, 2004; 94(3): 897 - 919.
|
|
|
|
|
|
D. M. TRALLI and L. R. JOHNSON Estimation of slowness-dependent source and receiver corrections for P-wave travel times Bulletin of the Seismological Society of America, December 1, 1986; 76(6): 1718 - 1738. [Abstract] [PDF]
|
|
|
|
|
|
S. J. HEARN and J. P. WEBB Relative teleseismic P residuals and upper mantle structure in eastern Queensland, Australia Bulletin of the Seismological Society of America, October 1, 1984; 74(5): 1661 - 1681. [Abstract] [PDF]
|
|
|
|
|
|
M. BARAZANGI and B. L. ISACKS A comparison of the spatial distribution of mantle earthquakes determined from data produced by local and by teleseismic networks for the Japan and Aleutian arcs Bulletin of the Seismological Society of America, December 1, 1979; 69(6): 1763 - 1770. [Abstract] [PDF]
|
|
|
|
|
|
C. LOMNITZ A fast epicenter location program Bulletin of the Seismological Society of America, April 1, 1977; 67(2): 425 - 431. [Abstract] [PDF]
|
|
|
|
|
|
G. G. SORRELLS, J. B. CROWLEY, and K. F. VEITH Methods for computing ray paths in complex geological structures Bulletin of the Seismological Society of America, February 1, 1971; 61(1): 27 - 53. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
