Relative Teleseismic Surface Wave Attenuation using

Transportable Array Data

Team QDP ONAustin Holland, Joshua Richardson, Weisen

Shen, Paul Ogwari

Motivation

Educational movies exist to observe wave phases and particle motions across US array stations

Relative attenuation movies for surface wave propagation across the US array may provide an educational outreach opportunity for understanding of decay throughout various geologic regimes at a variety of scales

Simple attenuation calculations of corrected amplitude reduction between stations can easily be calculated

Relative attenuation calculations yield an additional benefit of identifying faulty sensors, site effects and receiver effects

Final Product

Each station shaded in response to relative attenuation between adjacent stations for plane-wave approximated teleseismic travel paths

Extensive suite of maps produced at a full range of group velocities for Rayleigh and Love phases

Attenuation movies will be colored as surface waves reach stations, but will remain colored to produce a static suite of maps

Prototype Design

Display Rayleigh wave attenuation movie from M7.5 Chile earthquake in 2010

Include only one filtered group velocity for energy propigating northward along the long axis of the transportable array

Window energy empirically and base attenuation calculations off of the maximum absolute value amplitude between stations corrected for cylindrical spreading

Lessons Learned for Rapid Prototyping

We started with working code that did not do exactly what we wanted

Take the part that does exactly what you want

Get rid of the rest so as to keep the code clean and understandable

Collaborative code capability would have dramatically improved our time to a working prototype

Other Examples

Example Using Ambient Noise

Proposed Improvements

Calculate waveform envelopes for surface wave groups

Provide averaged map products for long-term teleseism surface wave attenuation for a full suite of azimuths

Provide exportable, geo-referenced products that can be compared to tomography studies, receiver function studies, ambient noise tomography studies, etc.