HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by LEHMANN, I. Search for Related Content GeoRef GeoRef Citation

The Hindu Kush earthquake of March 4, 1949 as recorded in Europe

LAMONT GEOLOGICAL OBSERVATORY COLUMBIA UNIVERSITY, PALISADES, NEW YORK

Abstract

The European records from distances 36°-50° of the deep Hindu Kush earthquake of March 4, 1949 were studied. The many clearly recorded deep-focus reflections lend to the records a characteristic appearance which is repeated in many other shocks from the same focal region. The ratios of the amplitudes of these phases vary somewhat from one shock to another. In the shock here considered sP and sPP are exceptionally large at most stations; in the Italian stations they are not so large, while pP is a clear phase. pP is not very well defined at most other stations.

Most of the 1949 records were from the old type long-period instruments having their highest magnification for periods from about 5 sec to 12 sec. Present day instruments of quite short or of very long proper period while admirable for many purposes do not record waves in this period range very well and therefore do not produce a satisfactory picture of the forerunners of earthquakes. The difference between the records obtained on different instruments is illustrated.

It is shown in examples that the amplitude ratio PP:P may differ strongly at the same epicentral distance and also that pP may vary greatly with azimuth.

The deficiency of station readings is noted.

Travel times and their residuals are tabulated and travel times plotted versus epicentral distances.

This article has been cited by other articles:

				M. NIAZI SH travel times and lateral heterogeneities in the lower mantle Bulletin of the Seismological Society of America, December 1, 1973; 63(6-1): 2035 - 2046. [Abstract] [PDF]

				E. R. KANASEWICH, T. ALPASLAN, and F. HORN The importance of S-wave precursors in shear-wave studies Bulletin of the Seismological Society of America, December 1, 1973; 63(6-1): 2167 - 2176. [Abstract] [PDF]

				H. A. DOYLE and A. L. HALES An analysis of the travel times of S waves to North American stations in the distance range 28{degrees} to 82{degrees} Bulletin of the Seismological Society of America, August 1, 1967; 57(4): 761 - 771. [Abstract] [PDF]