Bob Herrmann, Professor of Geophysics at Saint Louis University (USA), has made his fifth visit to ICTJA-CSIC to work with Antonio Villaseñor. Their interaction focused on the seismology of the crust. This work included the use of ambient noise and earthquake data to characterize surface wave dispersion, the joint inversion of the dispersion and receiver functions to constrain crustal velocity models, and the application of these models to the determination of earthquake moment tensors.

This set of common interests arises because both researchers have deployed seismic networks so they must manage large data sets and interpret the results. Herrmann benefits by being shown new data sets and the expectations of what must be determined from them. ICJTA-CSIC benefits by expressing research needs that Herrmann can address with his software.

During this year’s visit, they also revised a paper on the source parameters of the seismic activity registered near CASTOR offshore underground gas storage in 2013, by using an improved crustal model to be used with longer period digital data. Hermann, Villaseñor and their co-authors, Beatriz Gaite and Arantza Ugalde, found that the earthquakes are not as shallow as concluded by previous research. Herrmann modified and tested some code for the inversion of receiver functions so that local earthquake data can be used to focus on shallow geological structure.

Herrmann also developed a technique to address the question “I just installed a seismic network, I recorded some earthquakes, how do I define the magnitude of the earthquakes?”.

Herrmann arrived at ICTJA-CSIC on May 24th for a three weeks stay.