Origin of transverse surface waves

Determine the origin of transverse surface waves observed in earthquake records by identifying and explaining the physical mechanisms responsible for their generation and propagation in the Earth’s crust and upper mantle.

Background

In Appendix 1, a translated historical discussion explores how seismic waves reflect and transmit across interfaces and considers the possibility of a compliant or viscous magma layer. The analysis argues against a generally widespread magma layer based on attenuation and reflection behavior but acknowledges that the observed strong transverse vibrations (“second precursors”) need further interpretation.

Despite extensive theoretical considerations about shear-wave behavior in solids and viscous media, the text explicitly states that the origin of transverse surface waves remains unresolved and calls for more comprehensive observational comparisons to settle this question.