The Azores archipelago is a classic expression of a hotspot that has interacted with a mid-ocean ridge. A variety of geochemical studies and geophysical observations point to the influence of some sort of mantle plume on the formation of the Azores Plateau and the adjacent Mid-Atlantic Ridge (MAR), but the mantle structure beneath the Azores has not heretofore been imaged tomographically at a s...

In two earlier papers (Wallace et al., 1983, 1985), we discussed the evidence for tectonic release from underground nuclear explosions on Pahute Mesa at the Nevada Test Site (NTS) as observed in long-period body waves. It has been shown for some time that the nonisotropic component of the surface waves from most of these events could be explained by an equivalent double-couple source; namely st...

We have used broadband records from 18 teleseismic stations and three-component records from 16 local strongmotion stations in a formal inversion to determine the temporal and spatial distribution of slip during the earthquake. Separate inversions of the teleseismic (periods, 3Contribution No. 4935, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA ...

Abstract. Records from ocean bottom seismometers (OBSs) are highly contaminated by noise, which is much stronger compared to data most land stations, especially on the horizontal components. As a consequence, high energy of oceanic noise at frequencies below 1 Hz considerably complicates analysis teleseismic earthquake signals recorded OBSs. Previous studies suggested different approaches remov...

We simultaneously invert the strong-motion velocity records and the longand intermediate-period teleseismic P waveforms of the 19 September 1985 Michoacan, Mexico, earthquake to recover the distribution of slip on the fault using a point-by-point constrained and stabilized, least-squares inversion method. A fault plane with strike fixed at 300 ° and dip fixed at 14 ° is placed in the region of ...

[1] We use 3-D waveform modeling of LFEs (lowfrequency earthquakes) to investigate their relation to plate boundary structure along a linear transect in northern Cascadia. To account for crustal velocity heterogeneity, a smoothed 3-D model of subduction zone structure is assembled that incorporates constraints from regional tomographic and plate boundary models. Scattered phases within LFE wave...

During the roughly year-long Seismic Wave Exploration in the Lower Lithosphere (SWELL) pilot experiment in 1997/1998, eight ocean bottom instruments deployed to the southwest of the Hawaiian Islands recorded teleseismic Rayleigh waves with periods between 15 and 70 s. Such data are capable of resolving structural variations in the oceanic lithosphere and upper asthenosphere and therefore help u...