Reflected and minor phases in records of near-by earthquakes in southern California*

Abstract

The present paper is a direct continuation of a recent paper (Gutenberg, 1944a)
\nin which the author has discussed travel times of the major P and S phases recorded
\nat near-by stations for fifty southern California earthquakes. To facilitate the present
\ninvestigation of phases complicated by refraction and reflection, thorough
\nconsideration was given to the partition of energy into the various reflected and
\nrefracted waves at discontinuities and to the ratio of ground displacements to the
\nincident amplitudes at the surface of the earth (Gutenberg, 1944b). This seems
\ndesirable since the number of theoretically possible phases to be expected is very
\nlarge, considering the four layers in the earth's crust; consequently, any calculated
\ncurve can be "verified" by using small impulses to be found on most seismograms.
\nTherefore, clearly recognizable phases should be used in such investigations, and
\nonly calculated travel times for waves with amplitudes theoretically large enough
\nto be conspicuous.