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Measuring Basal Force Fluctuations of Debris Flows Using Seismic Recordings and Empirical Green's Functions

Allstadt, Kate E. and Farin, Maxime and Iverson, Richard M. and Obryk, Maciej K. and Kean, Jason W. and Tsai, Victor C. and Rapstine, Thomas D. and Logan, Matthew (2020) Measuring Basal Force Fluctuations of Debris Flows Using Seismic Recordings and Empirical Green's Functions. Journal of Geophysical Research. Earth Surface, 125 (9). Art. No. e2020JF005590. ISSN 2169-9003. https://resolver.caltech.edu/CaltechAUTHORS:20200826-103628260

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Abstract

We present a novel method for measuring the fluctuating basal normal and shear stresses of debris flows by using along‐channel seismic recordings. Our method couples a simple parameterization of a debris flow as a seismic source with direct measurements of seismic path effects using empirical Green's functions generated with a force hammer. We test this method using two large‐scale (8 and 10 m³) experimental flows at the U.S. Geological Survey debris‐flow flume that were recorded by dozens of three‐component seismic sensors. The seismically derived basal stress fluctuations compare well in amplitude and timing to independent force plate measurements within the valid frequency range (15–50 Hz). We show that although the high‐frequency seismic signals provide band‐limited forcing information, there are systematic relations between the fluctuating stresses and independently measured flow properties, especially mean basal shear stress and flow thickness. However, none of the relationships are simple, and since the flow properties also correlate with one another, we cannot isolate a single factor that relates in a simple way to the fluctuating forces. Nevertheless, our observations, most notably the gradually declining ratio of fluctuating to mean basal stresses during flow passage and the distinctive behavior of the coarse, unsaturated flow front, imply that flow style may be a primary control on the conversion of translational to vibrational kinetic energy. This conversion ultimately controls the radiation of high‐frequency seismic waves. Thus, flow style may provide the key to revealing the nature of the relationship between fluctuating forces and other flow properties.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2020jf005590DOIArticle
https://doi.org/10.7914/SN/YV_2017DOIData
https://doi.org/10.5066/P9NAFXW7DOIData
https://pubs.usgs.gov/of/2007/1315Related ItemVideos
ORCID:
AuthorORCID
Allstadt, Kate E.0000-0003-4977-5248
Farin, Maxime0000-0002-0250-2499
Iverson, Richard M.0000-0002-7369-3819
Obryk, Maciej K.0000-0002-8182-8656
Kean, Jason W.0000-0003-3089-0369
Tsai, Victor C.0000-0003-1809-6672
Rapstine, Thomas D.0000-0001-5939-9587
Logan, Matthew0000-0002-3558-2405
Additional Information:© 2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 07 September 2020; Version of Record online: 07 September 2020; Accepted manuscript online: 25 August 2020; Manuscript accepted: 19 August 2020; Manuscript revised: 17 July 2020; Manuscript received: 21 February 2020. We would like to acknowledge all the people who were instrumental in making the 2017 flume experiments happen, including Joel Smith, Chris Lockett, David George, Kelly Swinford, Corina Cerovski‐Darriau, John Perkins, Erin Bessette‐Kirton, Ben Mirus, and Francis Rengers. Nodal seismic instruments were provided by IRIS PASSCAL. V. C. T. acknowledges support from NSF EAR‐1939227. We also acknowledge Robert Anthony and three anonymous reviewers for their insightful reviews that helped substantially improve the manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Data Availability Statement: Seismic data from the 2017 flume experiments are available from the IRIS Data Management Center PH5 repository under network code YV (Allstadt, 2017, https://doi.org/10.7914/SN/YV_2017). Other data used in this study are available from USGS ScienceBase (Obryk & Iverson, 2019, https://doi.org/10.5066/P9NAFXW7). Video recordings of these two experiments and many other similar experiments are available for online viewing at https://pubs.usgs.gov/of/2007/1315 (Logan et al., 2018).
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR‐1939227
Subject Keywords:debris flow; seismology; Empirical Green's functions; flume; experiments
Issue or Number:9
Record Number:CaltechAUTHORS:20200826-103628260
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200826-103628260
Official Citation:Allstadt, K. E., Farin, M., Iverson, R. M., Obryk, M. K., Kean, J. W., & Tsai, V. C., et al. (2020). Measuring basal force fluctuations of debris flows using seismic recordings and empirical Green's functions. Journal of Geophysical Research: Earth Surface, 125, e2020JF005590. https://doi.org/10.1029/2020JF005590
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105117
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Aug 2020 19:17
Last Modified:17 Sep 2020 23:45

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