Evaluation of a snow avalanche possibly triggered by a local earthquake at Vallée de la Sionne, Switzerland

Abstract

Please cite this article as: Pérez-Guillén, C., Tapia, M., Furdada, G., Suriñach, E., McElwaine, J.N., Steinkogler, W., Hiller, M., Evaluation of a snow avalanche possibly triggered by a local earthquake at Vallée de la Sionne, Switzerland, Cold Regions Science and Technology (2014), doi: 10.1016/j.coldregions.2014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractSnow avalanches are moving sources of infrasonic and seismic energy. They can be triggered by many different mechanisms that include the shaking produced by earthquakes. The forces induced by an earthquake can cause an increase in the load down the slope and can also decrease the shear strength and both effects can cause the release of an avalanche. This phenomenon represents an important hazard associated with earthquakes in snow-covered mountain areas with high seismicity.On 6 December 2010 a snow avalanche was released at the experimental site of Vallée de la Sionne (VDLS) in Switzerland seconds after a local earthquake of magnitude A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 M L 3.1 with the hypocenter in France, approximately 43 km from the avalanche starting zone. The seismic and infrasound signals generated by the earthquake and the snow avalanche were recorded by an array of sensors installed at VDLS. This paper analyses these data and shows that the avalanche was possibly triggered by the earthquake. This analysis also allows us to determine the characteristics of the avalanche (type and path).The infrasound data shows that the time of the avalanche release coincided with the arrival of the seismic waves of the earthquake. We calculate the values of the ground vibration parameters (PGD, PGV, PGA, PSA, I a and TD) measured at the release area of the avalanche and compare them with those of two other earthquakes that did not trigger an avalanche. To evaluate the influence of the snowpack stratigraphy with the effectiveness of the earthquakes to trigger an avalanche, we simulate the snow cover using the one-dimensional snow cover model SNOWPACK. The weather and snow cover conditions of the days on which these events occurred are compared and used to evaluate the snowpack stability and the consequent likelihood of avalanche activity. The snowpack stability is the primary factor that determines whether an avalanche may be triggered by minor earthquakes. We conclude that when the snowpack is only marginally stable then the displacement caused by even a small earthquake could be enough to trigger an avalanche. Furthermore, the analysis of the other two, even stronger...

Snow Avalanche Detection and Source Constraints Made Using a Networked Array of Infrasound Sensors

“…Understanding the relationship between infrasound production and flow energetics will benefit from additional field experiments, involving multidisciplinary techniques such as radars and photogrammetric methods. Focused infrasound study incorporating these integrated observations, such as is routinely done at the Vallee de la Sionne (e.g., Köhler et al., 2016; Pérez‐Guillén et al., 2014), will provide vital validation for flow parameters that cannot be directly measured with infrasound remote sensing. Coupled infrasound and seismic wave analysis, which has been used on its own to quantify flow parameters (e.g., Lacroix et al., 2012; Marchetti et al., 2020; Van Herwijnen & Schweizer, 2011; Vilajosana et al., 2007), will be especially useful for understanding behaviors of avalanches of variable size, variable density, (e.g., wet vs. dry) and for different types of flow regimes including basal flow, fluidized, and suspension layers (Gauer et al., 2008).…”

Estimation of Avalanche Development and Frontal Velocities Based on the Spectrogram of the Seismic Signals Generated at the Vallée de la Sionne Test Site

“…The seismic data were obtained at stations equipped with a three-component seismometer Mark L-4C-3D (Mark Products) of eigenfrequency 1 Hz and a data acquisition system Reftek-130 (Trimble). One of the major advantages of our installation is that the seismic data recording system does not depend on a triggering system and obtains data continuously, allowing us to record the signals generated by the entire avalanche and other seismic events (e.g., earthquakes, [58]).…”

Triggering mechanisms of Gayari avalanche, Pakistan

“…Snow avalanche is large body of snow mass that flow over unstable slope (ZARUBA and RAPP, 1981;Hewitt, 2009;Fort et al, 2010), typically starts when a huge glacier is detached from its main body and moves downward at extremely high Centre for Earthquake Studies, Islamabad, Pakistan E-mail: bsaif429@gmail.com velocity (Davies and McSaveney, 2002). It is a main hazard source in mountainous region for infrastructures (roads, buildings) and peoples during winter season (Pérez-Guillén et al, 2014). Relationships between snow properties and meteorological conditions are controlling factors in slope failure (Perla, 1970;Mahboob et al, 2015).…”