Open AccessChange in Rayleigh wave phase velocity due to decrease of P-wave velocity before an earthquake
Author(s) -
S. N. Bhattacharya
Publication year - 1979
Publication title -
mausam
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.243
H-Index - 12
ISSN - 0252-9416
DOI - 10.54302/mausam.v30i2.3049
Subject(s) - phase velocity , rayleigh wave , group velocity , geology , wave velocity , crust , seismology , phase (matter) , s wave , homogeneous , surface wave , geodesy , physics , geophysics , optics , thermodynamics , petrology , quantum mechanics , shear (geology)
20per cent decrease of P-wave velocity has often been noted by many workers before an earthquake. Change in Rayleigh wave phase velocity due to such a decrease is studied so as to note the possibility of using the phase velocity change as one of the methods to predict earthquake. For this purpose theoretical phase velocity and its change due to the decrease of P-wave velocity have been obtained for a two-layered crustal model over a homogeneous mantle. 20 per cent decrease of P-wave velocity in the first layer gives a decrease of phase velocity by 4 per cent over a wide range of period with a maximum decrease of 4.8 per cent. While 20 per cent decrease of P-wave velocity in the both first and second layers of the crust gives a phase velocity decrease of 5 per cent over a wide range of period with a maximum decrease of 7.0 per cent.