CaltechTHESIS
  A Caltech Library Service

Crustal structure and reflections from the Mohorovičić discontinuity in southern California

Citation

Shor, George G. (1954) Crustal structure and reflections from the Mohorovičić discontinuity in southern California. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:02092010-093212931

Abstract

The thickness and structure of the crust of the earth have been studied in a limited area of southern California by means of reflected and refracted seismic waves. Two usable records of reflections from the Mohorovičić discontinuity at nearly vertical incidence were obtained from large quarry blasts. Each record shows a strong reflection with travel time near 10.6 sec. Strong reflections from the Mohorovičić discontinuity were also obtained at distances slightly beyond critical from blasts at one quarry. Many other records of blasts and of earthquakes snow phases that may be interpreted as reflections from the Mohorovičić discontinuity. Studies of refracted waves from blasts and earthquakes have given additional information about crustal velocities. When combined with the reflection data, they indicate that there is at least a slight decrease of velocity with depth somewhere in the crust and that there are significant variations in the arrival time of P_n at distant stations, indicating lateral variation either in crustal velocities or in the thickness of the crust. Computations of the thickness of the crust near Monolith and Corona, California have been made from various assumptions of velocity structure. The results obtained by using any model that agrees with the refraction data or by assuming a single-layer crust agree closely. In this area the Mohorovičić discontinuity is 32 km below sea level and the mean velocity in the crust is 6.2 km/sec.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Geophysics
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Richter, Charles Francis
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1954
Record Number:CaltechTHESIS:02092010-093212931
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:02092010-093212931
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5547
Collection:CaltechTHESIS
Deposited By: Tony Diaz
Deposited On:09 Feb 2010 17:51
Last Modified:26 Dec 2012 03:21

Thesis Files

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

20Mb
[img]
Preview
PDF - Supplemental Material
See Usage Policy.

20Mb
[img]
Preview
PDF - Supplemental Material
See Usage Policy.

19Mb
[img]
Preview
PDF - Supplemental Material
See Usage Policy.

41Mb
[img]
Preview
PDF - Supplemental Material
See Usage Policy.

11Mb

Repository Staff Only: item control page