Postdoctoral Researcher
ETH Geophysics, Seismology and Wave Physics
daniel.bowden@erdw.ethz.ch
I am committed to better characterizing seismic hazard, and want to advance our understanding of how waves move and amplify in the shallow crust. I am interested in all things related to seismic array processing, signal processing, and wave propagation physics.
Regarding site amplifications, we have found that a description of surface wave amplifications leads to frequency and amplitude predictions different from that of a vertically-incident shear wave. This challenges the standard underlying assumption in much of earthquake hazard analysis and engineering, and we are working to develop the formalism by which each type of wave can be properly accounted for.
Much of my research focuses on ambient noise tomography, and the extent to which crustal properties such as site-response, attenuation, and scattering can be resolved from signal amplitudes. Direct observations of the shallow crustal structure's effect on the ambient noise wavefield can be used to validate more traditional wave propagation methods for seismic hazard estimates.
Previous studies have included noise tomography with an OBS array offshore southern California, the deployment and analysis of a 3D broadband array at the Homestake Mine in South Dakaota, and the analysis of wavefronts propagating across big-N arrays like the UsArray and Long Beach Nodal array. More recently, I have been involved in learning about Distributed Acoustic Sensing (DAS) applications, for example in an urban setting under the city of Bern and on the Rhone glacier in Switzerland.
More on research
We're trying a new thing! Check out our group's YouTube Channel for video summaries of our research projects and papers:
- Our latest fiber sensing project in Istanbul, Turkey: [Video]
- Connecting different kinds of fiber-optic seismic sensing: [Video]
- On Beamforming and Noise Source Inversion: [Video]
A big thanks to Jonas Igel for filming and editing help.