Deep earth structure and dynamics using seismological tools. Earthquake processes and scaling laws. Real time estimation of earthquake parameters. Development of modern broadband seismic and geophysical observatories on land and in the oceans. Planetary seismology.
We document a high signal to noise phase that agrees with theoretical predictions for PKJKP. Envelope modeling of the PKJKP waveform implies a slightly larger shear velocity gradient with depth in the inner core than that in PREM model.
Abstract
The seismic phase PKJKP, which traverses the inner core as a shear wave, and would provide direct evidence for its solidity, has been difficult to detect. Using stacked broadband records from the Gra”fenberg array in Germany, we document a high signal to noise phase, whose arrival time and slowness agree with theoretical predictions for PKJKP. The back-azimuth of this arrival is also consistent with predictions for PKJKP as is the comparison with a pseudo-liquid inner core model. Envelope modeling of the PKJKP waveform implies a slightly larger shear velocity gradient with depth in the inner core than that in PREM model.
Tutorial on how to use Git and GitHub for team collaboration on a project. Content includes installing, setting up, creating a repository, making commits, un...
Barbara Romanowicz
less than 1 minute read
research-papers
Progressive crystallisation of Earth’s inner core drives convection in the outer core and magnetic field generation. Determining the rate and pattern of inne...
Using a regional tomographic model of the Alaskan upper mantle to predict upper mantle effects on PKP travel times, we show that the signature of the Alaska ...
Barbara Romanowicz
less than 1 minute read
research-papers
Based on the PKPdf observations and our new tomography model of the upper mantle beneath Alaska, we conclude that at least 2 s of the travel time anomaly oft...