CaltechAUTHORS
  A Caltech Library Service

New evidence for a change in physical conditions at depths near 100 kilometers

Gutenberg, B. and Richter, Charles F. (1939) New evidence for a change in physical conditions at depths near 100 kilometers. Bulletin of the Seismological Society of America, 29 (4). pp. 531-537. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20140804-163129443

[img]
Preview
PDF - Published Version
See Usage Policy.

1192Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20140804-163129443

Abstract

Comparative investigation of the seismograms of shallow earthquakes shows that the amplitudes of the first recorded longitudinal wave (Pn or P) vary considerably with distance from the epicenter. At distances up to 6° the seismograms are of "local shock" type, and the amplitude of Pn increases somewhat with distance. From 6° the amplitude decreases regularly, reaching a very small minimum near 14° (1500 km.). There is then a sudden increase, and the amplitudes continue large to beyond 20°. Together with the corresponding travel times, this suggests that at about 80 km. below the surface the velocity of longitudinal waves ceases to increase with depth, and probably decreases slightly through a limited range of depth, below which it again increases with depth. It is not yet settled whether the decrease is gradual throughout its range, or whether it takes place suddenly at a discontinuity.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://bssa.geoscienceworld.org/content/29/4/531.full.pdf+htmlPublisherArticle
Additional Information:Copyright © 1939, by the Seismological Society of America. Manuscript received for publication June 23, 1939.
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Balch Graduate School of the Geological Sciences Contribution277
Issue or Number:4
Record Number:CaltechAUTHORS:20140804-163129443
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140804-163129443
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47947
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:05 Aug 2014 15:14
Last Modified:03 Oct 2019 06:58

Repository Staff Only: item control page