The purpose of this paper is to present the fundamentally basic aspects of source spectra through the preliminary use of the one-dimensional Haskell source model which assumes a finite fault with a constant rupture velocity. Teleseismic distances are assumed, such that the far field term dominates, allowing the P and S waves emanating from the source to be effectively considered double couple p...

SUMMARY The densification of both permanent and temporary seismic networks has raised new interest in surface wave eikonal tomography from which phase velocity maps can be obtained without resolving a tomographic inverse problem. However, requires to reconstruct traveltime surfaces discrete number measurements at the station locations, challenging. We present method these with smoothing splines...

SUMMARY Secondary microseisms are caused by nonlinear interactions between ocean waves of approximately equal wavelengths and opposite propagation directions. This seismic forcing is evaluated using sea-state hindcast data further modulated the bathymetric effect. The numerical model provides a global activity representation secondary microseisms, from which we isolate major events. We backproj...

From an analysis of broadband teleseismic Pwaveforms we resolve the complex rupture characteristics of the 17 June 1996, Flores earthquake (Mw 7.9, depth 590 km). This earthquake was unusual because of its large rupture length and the variation in rupture velocity and stress drop. The 20 s rupture propagated westward at 2-3 km/s to a distance of 20-30 km, and eastward at 4 km/s over 75 km. Aver...

Reflectivity synthetic seismograms demonstrate that the type, layering and orientation of 1-D anisotropy influences strongly the coda of teleseismic P waves at periods T\1 sec, particularly P-SH converted waves. We assume the simplest form of anisotropy described by an elastic tensor with a symmetry axis ŵ of arbitrary orientation. The resulting phase velocities vary as cos 2j with respect to t...

By comparing records of the radial component of motion of teleseismic P waves to records of the vertical component, it is possible to identify S phases within the P wave form. These phases are generated by the mechanism of P to S conversion at discontinuities in velocity under the receiving station. Similar phases of the S to P converted type appear as precursors to the direct SV arrival. Model...

[1] Tomographic models based on hypothetically infinite frequency ray interpretation of teleseismic travel time shifts have revealed a region of relatively low P and S wave speeds extending from shallow mantle to 400 km depth beneath Iceland. In reality, seismic waves have finite frequency bandwidths and undergo diffractive wave front healing. The limitation in ray theory leaves large uncertain...