scholarly journals The mechanism of delayed release in earthquake-induced avalanches

2019 ◽  
Vol 475 (2227) ◽  
pp. 20190092 ◽  
Author(s):  
Alexander M. Puzrin ◽  
Thierry Faug ◽  
Itai Einav
Keyword(s):  
Shear Fracture ◽  
Central Italy ◽  
Rate Sensitivity ◽  
Western Himalaya ◽  
Basic Mechanism ◽  
Model Formulation ◽  
Strong Earthquakes ◽  
New Approach ◽  
Significant Damage ◽  
Basal Shear

Snow avalanches can be triggered by strong earthquakes. Most existing models assume that snow slab avalanches happen simultaneously during or immediately after their triggering. Therefore, they cannot explain the plausibility of delayed avalanches that are released minutes to hours after a quake. This paper establishes the basic mechanism of delays in earthquake-induced avalanche release using a novel analytical model that yields dynamics consistent with three documented cases, including two from Western Himalaya and one from central Italy. The mechanism arises from the interplay between creep, strain softening and strain-rate sensitivity of snow, which drive the growth of a basal shear fracture. Our model demonstrates that earthquake-triggered delayed avalanches are rare, yet possible, and could lead to significant damage, especially in long milder slopes. The generality of the model formulation opens a new approach for exploring many other problems related to natural slab avalanche release.

scholarly journals Can earthquakes lead to delayed avalanche release ?

2020 ◽  
Author(s):  
Alexander M. Puzrin ◽  
Thierry Faug ◽  
Itai Einav
Keyword(s):  
Strain Softening ◽  
Shear Fracture ◽  
Rate Sensitivity ◽  
Western Himalaya ◽  
Basic Mechanism ◽  
Snow Avalanches ◽  
Model Formulation ◽  
Strong Earthquakes ◽  
Abruzzo Region ◽  
Basal Shear

<p>Strong earthquakes often trigger snow avalanches, sometimes with observable delays. Most existing models assume that snow slab avalanches happen simulatenously during or immediatly after their triggering. Therefore, they cannot explain the plausibility of delayed avalanches that are released minutes to hours after a quake. Resolving this shortcoming is critical for improving safety, as emphasized by deadly delayed avalanches in Western Himalaya and, most recently, by the devastating Rigopiano avalanche in Italy’s Abruzzo region, which occurred more than 30 min after the last in a series of major quakes on 18 January 2017. This work establishes the basic mechanism of delays in earthquake-induced avalanche release using a novel analytical model that yields failure scenarios consistent with the Western Himalaya and Rigopiano cases. The mechanism arises from the interplay between creep, strain softening and strain-rate sensitivity of snow, which drive the growth of a basal shear fracture. Our results imply that earthquake-delayed avalanches are rare, yet possible, and could lead to significant damade, especially in long milder slopes. The generality of the model formulation opens a new avenue for exploring other questions related to natural slab avalanche release.</p>

scholarly journals Integrating macroseismic intensity distributions with a probabilistic approach: an application in Italy

2021 ◽  
Vol 21 (8) ◽  
pp. 2299-2311
Author(s):  
Andrea Antonucci ◽  
Andrea Rovida ◽  
Vera D'Amico ◽  
Dario Albarello
Keyword(s):  
Southern Italy ◽  
Central Italy ◽  
Probabilistic Approach ◽  
Source Characterization ◽  
Strong Earthquakes ◽  
Intensity Prediction ◽  
Macroseismic Intensities ◽  
Earthquake Effects ◽  
Available Information

Abstract. The geographic distribution of earthquake effects quantified in terms of macroseismic intensities, the so-called macroseismic field, provides basic information for several applications including source characterization of pre-instrumental earthquakes and risk analysis. Macroseismic fields of past earthquakes as inferred from historical documentation may present spatial gaps, due to the incompleteness of the available information. We present a probabilistic approach aimed at integrating incomplete intensity distributions by considering the Bayesian combination of estimates provided by intensity prediction equations (IPEs) and data documented at nearby localities, accounting for the relevant uncertainties and the discrete and ordinal nature of intensity values. The performance of the proposed methodology is tested at 28 Italian localities with long and rich seismic histories and for two well-known strong earthquakes (i.e., 1980 southern Italy and 2009 central Italy events). A possible application of the approach is also illustrated relative to a 16th-century earthquake in the northern Apennines.

scholarly journals Sequential Earthquake Damage Assessment Incorporating Optimized sUAV Remote Sensing at Pescara del Tronto

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 332 ◽  
Author(s):  
Michael Freeman ◽  
Cory Vernon ◽  
Bryce Berrett ◽  
Nicole Hastings ◽  
Jeff Derricott ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Central Italy ◽  
Time Lapse ◽  
Small Towns ◽  
Significant Damage ◽  
Planning Algorithm ◽  
Data Capturing ◽  
The Village ◽  
Large Earthquakes ◽  
Imagery Data

A sequence of large earthquakes in central Italy ranging in moment magnitudes (Mw) from 4.2 to 6.5 caused significant damage to many small towns in the area. After each earthquake in 2016 (24 August and 26 October), automated small unmanned aerial vehicles (sUAV) acquired valuable imagery data for post-hazard reconnaissance in the mountain village of Pescara del Tronto, and were applied to 3D reconstruction using Structure-from-Motion (SfM). In July 2018, the site was again monitored to obtain additional imagery data capturing changes since the last visit following the 30 October 2016 Earthquake. A genetic-based mission-planning algorithm that delivers optimal viewpoints and path planning was field tested and reduced the required photos for 3D reconstruction by 9.1%. The optimized 3D model provides a better understanding of the current conditions of the village, when compared to the nadir models, by containing fewer holes on angled surfaces, including an additional 17% surface area, and with a comparable ground-sampling distance (GSD) of ≈2.4 cm/px (≈1.5 cm/px when adjusted for camera pixel density). The resulting three time-lapse models provide valuable metrics for ground motion, progression of damage, resilience of the village, and the recovery progress over a span of two years.

Characterizing Aftershock Sequences of the Recent Strong Earthquakes in Central Italy

2017 ◽  
Vol 174 (10) ◽  
pp. 3713-3723 ◽  
Author(s):  
Vladimir G. Kossobokov ◽  
Anastasia K. Nekrasova
Keyword(s):  
Central Italy ◽  
Strong Earthquakes ◽  
Aftershock Sequences

scholarly journals Validation of a New Aluminum Honeycomb Crush Model With Dynamic Impact Tests

2007 ◽  
Author(s):  
Terry Hinnerichs ◽  
William Scherzinger ◽  
Mike Nielsen ◽  
Tom Carne ◽  
Eric Stasiunas ◽  
...  
Keyword(s):  
Finite Element ◽  
Rate Sensitivity ◽  
Element Model ◽  
Test Results ◽  
Dynamic Impact ◽  
New Approach ◽  
Test Parameters ◽  
Aluminum Honeycomb ◽  
Impact Simulations ◽  
Constitutive Parameters

This paper describes a process for validating a new constitutive model for large, high strain-rate deformation of aluminum honeycomb, called the Honeycomb Crush Model (HCM). This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. The HCM has been implemented in the transient dynamic Presto finite element code for dynamic impact simulations. The HCM constitutive parameters were identified based on Presto finite element models that were used to simulate uniaxial and biaxial crush tests of 38 lb/ft3 aluminum honeycomb and reported in an earlier paper. This paper focuses on validating the HCM in the Presto code for application to impact situations that have honeycomb crush velocities up to 85 ft/sec. Also, a new approach for incorporating rate sensitivity into the model is described. A two-stage energy absorber with integrated aluminum honeycomb is described as the configuration for dynamic impact validation experiments. The test parameters and finite element model will be described along with the uncertainty quantification that was done and propagated through the model. Finally, correlation of model predictions and test results will be presented using an energy based validation metric.

scholarly journals Analysis of the 2016 Amatrice earthquake macroseismic data

2016 ◽  
Vol 59 ◽  
Author(s):  
Lorenzo Hofer ◽  
Mariano Angelo Zanini ◽  
Flora Faleschini
Keyword(s):  
Critical Analysis ◽  
Seismic Event ◽  
Residential Buildings ◽  
Central Italy ◽  
Macroseismic Data ◽  
Significant Damage ◽  
Macroseismic Scale ◽  
The University ◽  
2016 Amatrice Earthquake ◽  
Macroseismic Survey

On August 24, 2016, a sudden MW 6.0 seismic event hit Central Italy, causing 298 victims and significant damage to residential buildings and cultural heritage. In the days following the mainshock, a macroseismic survey was conducted by teams of the University of Padova, according to the European Macroseismic Scale (EMS98). In this contribution, a critical analysis of the collected macroseismic data is presented and some comparisons were performed with the recent 2012 Emilia sequence.

scholarly journals Earthquake-Induced Spring Discharge Modifications: The Pescara di Arquata Spring Reaction to the August–October 2016 Central Italy Earthquakes

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 767 ◽  
Author(s):  
Daniela Valigi ◽  
Davide Fronzi ◽  
Costanza Cambi ◽  
Giulio Beddini ◽  
Carlo Cardellini ◽  
...  
Keyword(s):  
Central Italy ◽  
Standardized Precipitation Index ◽  
Spring Discharge ◽  
Strong Earthquakes ◽  
Drinking Purposes ◽  
Subsequent Decrease ◽  
Dry Conditions ◽  
Groundwater Regime ◽  
Monthly Discharge ◽  
The Standardized Precipitation Index

Co-seismic changes in groundwater regime are often observed after moderate to strong earthquakes. The 24 August 2016 Mw 6.0 extensional Amatrice earthquake, which was the first event of a long-lasting seismic sequence, including the 30 October 2016 Mw 6.5 Norcia event, triggered a significant discharge alteration to the Pescara di Arquata spring, located in the Umbria-Marche Apennines (Northern Apennines, Central Italy) and exploited for drinking purposes. During the first five months after the first mainshock, an extra flow of about 30% was recorded, while both water chemistry and temperature did not show significant changes. Thereafter, the spring discharge decreased significantly, and at the end of 2019 it was still lower than normal. The Standardized Precipitation Index (SPI) indicates that these low mean monthly discharge values are not related to particularly dry conditions. The increase in post-seismic depletion coefficients indicates that the aquifer empties faster than it did during the inter-seismic period. The observed transient increase and subsequent decrease of discharge are consistent with a transient, earthquake-related increase in hydraulic conductivity.

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