Periodic Variations of the Gravitational Force. A Gravity Survey in the Monk Hill Area. Transmission of Shot Impulses in Shallow Water

Citation

Geldart, Lloyd Philip (1949) Periodic Variations of the Gravitational Force. A Gravity Survey in the Monk Hill Area. Transmission of Shot Impulses in Shallow Water. Engineer's thesis, California Institute of Technology. doi:10.7907/YH1P-CT82. https://resolver.caltech.edu/CaltechTHESIS:08172010-101104666

Abstract

Part I: Using a La Coste and Romberg gravimeter, readings were taken every half hour for 72 hours immediately preceding full moon in the sub-basement of Mudd Building, California Institute of Technology, and for 56 hours immediately following in the interferometer building on Mount Wilson. Observed values were compared with values calculated on the hypothesis of a rigid earth, the results showing more yielding at Mount Wilson (22%) than at Mudd Building (16%). Effects due to ocean tides and barometric changes were estimated. After the removal of drift and earth tide effects, the residuals showed periods of 24, 12, 6, and 2 hours, the 24 hour period being very strong at Mount Wilson.

Part II: Using a La Coste and Rombert gravimeter, gravity values were obtained at 65 stations in the vicinity of Monk Hill, Pasadena. A density value for elevation corrections was obtained using a least squares method and data obtained with a network of 35 stations in Washington Park. A topographical correction was also made for the San Gabriel Mountains to the north of the area.

The corrected gravity data were used to calculate elevations of the basement along Howard Street, and the resulting basement profile compared with one obtained by a seismograph survey.

Part III: The properties of various types of waves set up by underwater explosions is discussed from the viewpoint of their application in locating shot points in seismic work carried on over water. The construction of the audio amplifiers and filters used to record these waves is described, together with the results of a preliminary check of their performance.

Item Type:

Thesis (Engineer's thesis)

Subject Keywords:

gravitational force, gravimeter, Mt. Wilson, Raymond Basin, San Rafael Hills, Monk Hill, ground waves, water waves ; Geophysics

Degree Grantor:

California Institute of Technology

Division:

Geological and Planetary Sciences

Major Option:

Geophysics

Thesis Availability:

Public (worldwide access)

Research Advisor(s):

Dix, Charles Hewitt

Thesis Committee:

Unknown, Unknown

Defense Date:

1 January 1949

Additional Information:

Supplemental Files Information: Curves of g_o, g_c, ø and c’r for Pasadena: Supplement 1 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Curves for calculations of g: Supplement 2 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Curves of g_o, g_c, ø, and c’r for Mount Wilson: Supplement 3 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Gravity profiles along Howard Street: Supplement 4 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Comparison of various calculated basement profiles: Supplement 5 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Barometric pressure and height of ocean tides for Pasadena and Mount Wilson: Supplement 6 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis). Gravity map of the Monk Hill area: Supplement 7 from "Periodic variations of the gravitational force. A gravity survey in the Monk Hill area. Transmission of shot impulses in shallow water." (Thesis).

Record Number:

CaltechTHESIS:08172010-101104666

Persistent URL:

https://resolver.caltech.edu/CaltechTHESIS:08172010-101104666

DOI:

10.7907/YH1P-CT82

Related URLs:

URL	URL Type	Description
https://doi.org/10.22002/D1.351	DOI	Supplement 1 in CaltechDATA: Curves of g_o, g_c, ø and c’r for Pasadena
https://doi.org/10.22002/D1.352	DOI	Supplement 2 in CaltechDATA: Curves for calculations of g
https://doi.org/10.22002/D1.353	DOI	Supplement 3 in CaltechDATA: Curves of g_o, g_c, ø, and c’r for Mount Wilson
https://doi.org/10.22002/D1.354	DOI	Supplement 4 in CaltechDATA: Gravity profiles along Howard Street
https://doi.org/10.22002/D1.355	DOI	Supplement 5 in CaltechDATA: Comparison of various calculated basement profiles
https://doi.org/10.22002/D1.356	DOI	Supplement 6 in CaltechDATA: Barometric pressure and height of ocean tides for Pasadena and Mount Wilson
https://doi.org/10.22002/D1.357	DOI	Supplement 7 in CaltechDATA: Gravity map of the Monk Hill area