Effect of snowfall on changes in relative seismic velocity measured by ambient noise correlation

• Published in: The Cryosphere
• Main Authors: A. Guillemot, A. van Herwijnen, E. Larose, S. Mayer, L. Baillet
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-15-5805-2021; https://doaj.org/article/13c380dd04694f8c9ba326587825fd95

In mountainous, cold temperate and polar sites, the presence of snow cover can affect relative seismic velocity changes ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="normal">d</mi><mi>V</mi><mo>/</mo><mi>V</mi></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="a6ffee62df424f5e661296a90ad3d8c3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-15-5805-2021-ie00001.svg" width="25pt" height="14pt" src="tc-15-5805-2021-ie00001.png"/></svg:svg> ) derived from ambient noise correlation, but this relation is relatively poorly documented and ambiguous. In this study, we analyzed raw seismic recordings from a snowy flat field site located above Davos (Switzerland), during one entire winter season (from December 2018 to June 2019). We identified three snowfall events with a substantial response of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="normal">d</mi><mi>V</mi><mo>/</mo><mi>V</mi></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c874d20e792f2c6b91f6b526037592c9"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-15-5805-2021-ie00002.svg" width="25pt" height="14pt" src="tc-15-5805-2021-ie00002.png"/></svg:svg> measurements (drops of several percent between 15 and 25 Hz), suggesting a detectable change in elastic properties of the medium due to the additional fresh snow. To better interpret the measurements, we used a physical model to compute frequency-dependent changes in the Rayleigh wave velocity computed before and after the events. Elastic parameters of the ...