Investigation of the Alaskan earthquake of May 4, 1934.

• Main Author: Fillippone, Walter Ross
• Format: Others
• Published: 1944
• Online Access: https://thesis.library.caltech.edu/5666/1/Fillippone_wr_1944.pdf; Fillippone, Walter Ross (1944) Investigation of the Alaskan earthquake of May 4, 1934. Master's thesis, California Institute of Technology. doi:10.7907/HZ0X-MM45. https://resolver.caltech.edu/CaltechTHESIS:03312010-142759917 <https://resolver.caltech.edu/CaltechTHESIS:03312010-142759917>

<p>The shock investigated occurred on May 4, 1934 at 4h. 36m. 10s. The epicenter given in The International Seismological Summary for 1934 is 61.5 degrees north latitude, 147.5 degrees west longitude and the probably error of the epicenter is ± 0.21 degrees.</p> <p>The procedure of investigation consisted of using the S-P interval to find the origin time and subtracting the mean from the given times of P. However, when the residuals of given distance minus calculated distance was plotted against the azimuth, the resulting sine curve was displaced from the zero residual by three (3) seconds, indicating an incorrect origin time. A second origin time, 0 = zero, was calculated from the equation, 0 = (pP+P)/2 – (t_p+c), and the residuals plotted. The resulting curve was symmetric to the zero residual line and showed the epicenter to be 0.3 degrees to the south of its given location.</p> <p>The depth of focus was determined from the intervals of pP-P, sP-P, sS-S, PcP-P, and ScS-S, each interpolated from the corresponding tables in the reference papers.</p>