Preprints
https://doi.org/10.5194/tc-2020-38
https://doi.org/10.5194/tc-2020-38

  24 Feb 2020

24 Feb 2020

Review status: this preprint was under review for the journal TC but the revision was not accepted.

Acoustic Emission investigation for avalanche formation and release: A case study of dry-slab avalanche event in Great Himalaya

Jagdish Kapil1, Sakshi Sharma1,2, Karmjit Singh1, Jangvir Singh Shahi2, and Rama Arora3 Jagdish Kapil et al.
  • 1RDC- Snow and Avalanche Study Establishment, Chandigarh (UT) -160036, India
  • 2Department of Physics, Panjab University, Chandigarh (UT) -160014, India
  • 3Department of Physics, PGGC, Sector 11, Chandigarh (UT)160011, India

Abstract. Non-invasive monitoring of avalanche formation and release processes, through the use of Acoustic Emission (AE) technique, has been a research challenge since long time. In present investigation AE technique is implemented to monitor the avalanche formation and release processes through a case study of a natural avalanche event reported in Great Himalaya. The specialized AE sensor-arrestor arrays, established over the avalanche starting zone, in conjunction to a high speed multichannel AE acquisition system have successfully recorded the avalanche event passed through the course of instability development followed by release of avalanche. A new method is devised to compute the AE based instability index, and same has been applied to quantify the instability levels of a snowpack. The prominent AE parameters and instability indices are analyzed for different window scales with respect to different AE sensors. The effect of nivological and meteorological conditions and pit analyses collected during the avalanche formation process is also discussed. The critical instability was triggered possibly due to the excessive loading (during snowfall) of an unstable snowpack consisting of persistent weak layers which led to the avalanche release. An abnormal and abrupt increase in the AE activity was observed prior to the avalanche release. The increasing trends in instability indices have shown a good correlation to the avalanche formation and a sharp jump in instability index is attributed to a particular transition occurring across two different instability states of the snowpack. Thus, five conceptual states of snowpack are identified for instability evolution corresponding to four different transitions during avalanche formation and release processes.

Jagdish Kapil et al.

 
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Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Jagdish Kapil et al.

Jagdish Kapil et al.

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Short summary
A case study is presented for an avalanche event reported in Great Himalaya through monitoring and interpretation of the acoustic emission (AE) signatures detected by an AE sensor array established over avalanche slope. A peculiar AE activity and also the increasing trends of instability index have clearly demonstrated how avalanche was developed prior to its release. Several states of the snowpack are derived directly in terms of the AE which could be used as alert prior to avalanche occurence.