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dc.contributor.authorMichel, Abigail
dc.contributor.authorKean, Jason W.
dc.contributor.authorSmith, Joel B.
dc.contributor.authorAllstadt, Kate E.
dc.contributor.authorCoe, Jeffrey A.
dc.date.accessioned2019-08-23T16:04:47Z
dc.date.available2019-08-23T16:04:47Z
dc.date.issued2019
dc.description.abstractThe destructive nature of debris flows makes it difficult to quantify flow dynamics with direct instrumentation. For this reason, seismic sensors placed safely away from the flow path are often used to identify the timing and speed of debris flows. While seismic sensors have proven to be a valuable tool for event detection and early warning, their potential for identifying other aspects of debris flows (such as sediment concentration) is less studied. Here, we use two monitoring sites to investigate the extent to which debris-flow dynamics can be decoded from ground vibrations. One site is a bedrock channel in a steep semiarid basin in central Colorado (Chalk Cliffs), and the other is in a debris-flow channel incised in alluvium in a recently burned area in southern California (Van Tassel). At both sites, seismic data are measured with geophones (4.5 Hz) mounted next to the channels and sampled at high frequencies (500-1000 Hz). Independent constraints on flow dynamics are provided by laser distance meters to record flow stage (at 10 Hz) and high-definition video cameras to record flow velocity and qualitative estimates of sediment concentration. The observed debris flows at Chalk Cliffs typically consist of a series of short-duration (~30 second) surges with total durations of <40 minutes and have coarse-grained fronts and fluid-rich tails. In contrast, the events at Van Tassel are longer duration flows (>40 minutes) that begin as debris flows and transform into more steady debris floods. The arrangement of sensors at both sites allows us to identify correlations between vertical ground velocity, frequency, flow stage, and qualitative estimates of sediment concentration.
dc.format.mediumborn digital
dc.format.mediumproceedings (reports)
dc.identifier.urihttps://hdl.handle.net/11124/173224
dc.identifier.urihttp://dx.doi.org/10.25676/11124/173224
dc.languageEnglish
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.publisher.originalAssociation of Environmental and Engineering Geologists
dc.relation.ispartofSeventh International Conference on Debris-Flow Hazards Mitigation - Proceedings
dc.relation.ispartofAssociation of Environmental and Engineering Geologists; special publication 28
dc.rightsCopyright of the original work is retained by the authors.
dc.sourceContained in: Proceedings of the Seventh International Conference on Debris-Flow Hazards Mitigation, Golden, Colorado, USA, June 10-13, 2019, https://hdl.handle.net/11124/173051
dc.subjectdebris flow
dc.subjectflood
dc.subjectseismic
dc.subjectground vibrations
dc.subjectpost-wildfire
dc.subjectchannel
dc.subjectfrequency
dc.subjectspectrum
dc.subjectColorado
dc.subjectCalifornia
dc.titleTaking the pulse of debris-flows: extracting debris-flow dynamics from good vibrations in southern California and central Colorado
dc.typeText


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