Special Session: Adaptation of New Technologies and Methods to Drive New Discoveries in Seismology and Geodesy
Type: Oral
Day: 5/17/2018
Time: 2:00 PM
Room: Monroe
Abstract
We mapped at a global scale the Gutenberg-Richter parameters and the average seismic energy release rate using a novel multiscale approach. This approach consist essentially in considering all the possible spatial scales around a given point and extracting a robust median from the computed b-values. This approach has been shown to have the capability of determining automatically the spatial scales relevant to the considered dataset without "a priori" choices. The determination of the a-value is hence straightforward and allows computing the average seismic energy release rate. Interesting by-products of this computation are the determination of the relevant spatial scale and of the completeness magnitude.
For the purposes of this work we considered earthquakes from the USGS catalog located after 1973 and having a magnitude equal or higher than 4. The datased consists of about 400,000 events, with about half of them being located within the crust. Using these data we realized two global maps with a 25 km spatial resolution. The first map considers only the crustal seismicity discarding the depth information. It required the computation of multiscale b-values for about 1 million points. The second takes into account also the depth information, allowing to image the depth distribution of the b-value related to the deep seismicity. This 3D map required the computation over about 30 million points. Both maps required massive HPC computing with a total computation time of few weeks.
We show spatial variation of the b-value and of the average energy release rates for the crust in different geodynamic environments. In particular we focus on the Euro-Mediterranean region and North-America. For the 3D map we show some relevant result about variations along subducting slabs, in particular we present 3D maps for the Nazca slab.
Author(s):
D'Auria L. Instituto Volcanológico de Canarias (INVOLCAN)
Barrancos J. Instituto Volcanológico de Canarias (INVOLCAN)
García-Hernández R. Instituto Volcanológico de Canarias (INVOLCAN)
Padilla G. D. Instituto Volcanológico de Canarias (INVOLCAN)
Multiscale Analysis of the Global Seismicity
Category
Adaptation of New Technologies and Methods to Drive New Discoveries in Seismology and Geodesy