Debris flow magnitude estimation based on infrasound and seismic signals

2020 ◽  
Author(s):  
Andreas Schimmel ◽  
Matteo Cesca ◽  
Pierpaolo Macconi ◽  
Velio Coviello ◽  
Francesco Comiti
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Warning System ◽  
Early Warning Systems ◽  
Peak Discharge ◽  
Detection Methods ◽  
Mountain Areas ◽  
Detection And Identification ◽  
European Mountain ◽  
The Alps

<p>With the rapid socio-economic development of European mountain areas, the automatic detection and identification of mass movements like landslides, debris flows, and avalanches become more and more important to mitigate related risks by means of early warning systems. Past studies showed that such processes induce characteristic seismic and acoustic signals, the latter mostly in the infrasonic spectrum which can thus be used for event detection. Several investigations have already addressed signal processing and detection methods based on seismic or infrasound sensors. However, for developing an efficient warning system, not only the detection of events is important but also the identification of the event type (e.g. debris flow vs debris flood) and the estimation of its magnitude. So far, no method for such objectives has been developed which is based on the combination of both seismic and infrasonic signals.</p><p>This work presents a first approach to identify debris flows and debris floods magnitude based on the integration of infrasound and seismic data. First analysis shows that, for peak discharge, the use of infrasound amplitudes with a power curve fitting offers a good approach for finding an initial relationship between the recorded signals and this event parameter. For an estimation of the total volume, the discharge calculated with the relationship for peak discharge is integrated over the entire detection time of an event. Calculation of the peak discharge based on infrasound data offers a good approximation, but, for the calculation of the total volume, this method shows still a wide variance.</p><p>The method will be applied to seismic and infrasound data collected on three different test sites in the Alps: Gadria (South Tyrol, Italy), Lattenbach (Tyrol, Austria), and Cancia (Belluno, Italy).</p>

scholarly journals Acoustic module of the Acquabona (Italy) debris flow monitoring system

2005 ◽  
Vol 5 (2) ◽  
pp. 211-215 ◽  
Author(s):  
A. Galgaro ◽  
P. R. Tecca ◽  
R. Genevois ◽  
A. M. Deganutti
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Regression Line ◽  
Front Velocity ◽  
Peak Discharge ◽  
Physical Parameters ◽  
Flow Depth ◽  
Ground Vibrations ◽  
Mountain Areas ◽  
Flow Monitoring

Abstract. Monitoring of debris flows aimed to the assessment of their physical parameters is very important both for theoretical and practical purposes. Peak discharge and total volume of debris flows are crucial for designing effective countermeasures in many populated mountain areas where losses of lives and property damage could be avoided. This study quantifies the relationship between flow depth, acoustic amplitude of debris flow induced ground vibrations and front velocity in the experimental catchment of Acquabona, Eastern Dolomites, Italy. The analysis of data brought about the results described in the following. Debris flow depth and amplitude of the flow-induced ground vibrations show a good positive correlation. Estimation of both mean front velocity and peak discharge can be simply obtained monitoring the ground vibrations, through geophones installed close to the flow channel; the total volume of debris flow can be so directly estimated from the integral of the ground vibrations using a regression line. The application of acoustic technique to debris flow monitoring seems to be of the outmost relevance in risk reduction policies and in the correct management of the territory. Moreover this estimation is possible in other catchments producing debris flows of similar characteristics by means of their acoustic characterisation through quick and simple field tests (Standard Penetration Tests and seismic refraction surveys).

scholarly journals Learning Case Study of a Shallow-Water Model to Assess an Early-Warning System for Fast Alpine Muddy-Debris-Flow

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 750
Author(s):  
Antonio Pasculli ◽  
Jacopo Cinosi ◽  
Laura Turconi ◽  
Nicola Sciarra
Keyword(s):  
Debris Flow ◽  
Shallow Water ◽  
Early Warning ◽  
Debris Flows ◽  
Early Warning System ◽  
Warning System ◽  
Extreme Weather Events ◽  
Water Model ◽  
Computational Time ◽  
Processing Unit

The current climate change could lead to an intensification of extreme weather events, such as sudden floods and fast flowing debris flows. Accordingly, the availability of an early-warning device system, based on hydrological data and on both accurate and very fast running mathematical-numerical models, would be not only desirable, but also necessary in areas of particular hazard. To this purpose, the 2D Riemann–Godunov shallow-water approach, solved in parallel on a Graphical-Processing-Unit (GPU) (able to drastically reduce calculation time) and implemented with the RiverFlow2D code (version 2017), was selected as a possible tool to be applied within the Alpine contexts. Moreover, it was also necessary to identify a prototype of an actual rainfall monitoring network and an actual debris-flow event, beside the acquisition of an accurate numerical description of the topography. The Marderello’s basin (Alps, Turin, Italy), described by a 5 × 5 m Digital Terrain Model (DTM), equipped with five rain-gauges and one hydrometer and the muddy debris flow event that was monitored on 22 July 2016, were identified as a typical test case, well representative of mountain contexts and the phenomena under study. Several parametric analyses, also including selected infiltration modelling, were carried out in order to individuate the best numerical values fitting the measured data. Different rheological options, such as Coulomb-Turbulent-Yield and others, were tested. Moreover, some useful general suggestions, regarding the improvement of the adopted mathematical modelling, were acquired. The rapidity of the computational time due to the application of the GPU and the comparison between experimental data and numerical results, regarding both the arrival time and the height of the debris wave, clearly show that the selected approaches and methodology can be considered suitable and accurate tools to be included in an early-warning system, based at least on simple acoustic and/or light alarms that can allow rapid evacuation, for fast flowing debris flows.

scholarly journals Debris flows on forested cones – reconstruction and comparison of frequencies in two catchments in Val Ferret, Switzerland

2007 ◽  
Vol 7 (2) ◽  
pp. 207-218 ◽  
Author(s):  
M. Bollschweiler ◽  
M. Stoffel
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Historical Knowledge ◽  
Study Region ◽  
Sampling Height ◽  
The Alps ◽  
Recurrence Intervals ◽  
Study Sites ◽  
Flow Activity ◽  
Different Characteristics

Abstract. Debris flows represent a major threat to infrastructure in many regions of the Alps. Since systematic acquisition of data on debris-flow events in Switzerland only started after the events of 1987, there is a lack of historical knowledge on earlier debris-flow events for most torrents. It is therefore the aim of this study to reconstruct the debris-flow activity for the Reuse de Saleinaz and the La Fouly torrents in Val Ferret (Valais, Switzerland). In total, 556 increment cores from 278 heavily affected Larix decidua Mill., Picea abies (L.) Karst. and Pinus sylvestris L. trees were sampled. Trees on the cone of Reuse de Saleinaz show an average age of 123 years at sampling height, with the oldest tree aged 325 years. Two periods of intense colonization (the 1850s–1880s and the 1930s–1950s) are observed, probably following high-magnitude events that would have eliminated the former forest stand. Trees on the cone of Torrent de la Fouly indicate an average age of 119 years. As a whole, tree-ring analyses allowed assessment of 333 growth disturbances belonging to 69 debris-flow events. While the frequency for the Reuse de Saleinaz study site comprises 39 events between AD 1743 and 2003, 30 events could be reconstructed at the Torrent de la Fouly for the period 1862–2003. Even though the two study sites evince considerably different characteristics in geology, debris-flow material and catchment morphology, they apparently produce debris flows at similar recurrence intervals. We suppose that, in the study region, the triggering and occurrence of events is transport-limited rather than weathering-limited.

scholarly journals 2D Runout Modelling of Hillslope Debris Flows, Based on Well-Documented Events in Switzerland

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 70 ◽  
Author(s):  
Florian Zimmermann ◽  
Brian W. McArdell ◽  
Christian Rickli ◽  
Christian Scheidl
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Mass Movement ◽  
Clay Content ◽  
Systematic Evaluation ◽  
Mountain Areas ◽  
Flow Processes ◽  
Friction Parameters ◽  
Cohesive Interaction ◽  
Hillslope Debris Flow

In mountain areas, mass movements, such as hillslope debris flows, pose a serious threat to people and infrastructure, although size and runout distances are often smaller than those of debris avalanches or in-channel-based processes like debris floods or debris flows. Hillslope debris-flow events can be regarded as a unique process that generally can be observed at steep slopes. The delimitation of endangered areas and the implementation of protective measures are therefore an important instrument within the framework of a risk analysis, especially in the densely populated area of the alpine region. Here, two-dimensional runout prediction methods are helpful tools in estimating possible travel lengths and affected areas. However, not many studies focus on 2D runout estimations specifically for hillslope debris-flow processes. Based on data from 19 well-documented hillslope debris-flow events in Switzerland, we performed a systematic evaluation of runout simulations conducted with the software Rapid Mass Movement Simulation: Debris Flow (RAMMS DF)—a program originally developed for runout estimation of debris flows and snow avalanches. RAMMS offers the possibility to use a conventional Voellmy-type shear stress approach to describe the flow resistance as well as to consider cohesive interaction as it occurs in the core of dense flows with low shear rates, like we also expect for hillslope debris-flow processes. The results of our study show a correlation between the back-calculated dry Coulomb friction parameters and the percentage of clay content of the mobilised soils. Considering cohesive interaction, the performance of all simulations was improved in terms of reducing the overestimation of the observed deposition areas. However, the results also indicate that the parameter which accounts for cohesive interaction can neither be related to soil physical properties nor to different saturation conditions.

scholarly journals Study on the combined threshold for gully-type debris flow early warning

2019 ◽  
Vol 19 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Jian Huang ◽  
Theodoor Wouterus Johannes van Asch ◽  
Changming Wang ◽  
Qiao Li
Keyword(s):  
Debris Flow ◽  
Pore Pressure ◽  
Early Warning ◽  
Early Stage ◽  
Warning System ◽  
Early Warning Systems ◽  
Great Loss ◽  
Mountainous Regions ◽  
Pressure Threshold

Abstract. Gully-type debris flow induced by high-intensity and short-duration rainfall frequently causes great loss of properties and causalities in mountainous regions of southwest China. In order to reduce the risk by geohazards, early warning systems have been provided. A triggering index can be detected in an early stage by the monitoring of rainfall and the changes in physical properties of the deposited materials along debris flow channels. Based on the method of critical pore pressure for slope stability analysis, this study presents critical pore pressure threshold in combination with rainfall factors for gully-type debris flow early warning. The Wenjia gully, which contains an enormous amount of loose material, was selected as a case study to reveal the relationship between the rainfall and pore pressure by field monitoring data. A three-level early warning system (zero, attention, and warning) is adopted and the corresponding judgement conditions are defined in real time. Based on this threshold, there are several rainfall events in recent years have been validated in Wenjia gully, which prove that such a combined threshold may be a reliable approach for the early warning of gully-type debris flow to safeguard the population in the mountainous areas.

scholarly journals Eighty Years of Data Collected for the Determination of Rainfall Threshold Triggering Shallow Landslides and Mud-Debris Flows in the Alps

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 133 ◽  
Author(s):  
Fabio Luino ◽  
Jerome De Graff ◽  
Anna Roccati ◽  
Marcella Biddoccu ◽  
Chiara Giorgia Cirio ◽  
...  
Keyword(s):  
Debris Flows ◽  
Rainfall Threshold ◽  
Shallow Landslides ◽  
Mean Annual Precipitation ◽  
Economic Damage ◽  
Landslide Risk ◽  
Mountain Areas ◽  
Knowledge Framework ◽  
Rain Gauges ◽  
The Alps

Identifying the minimum rainfall thresholds necessary for landslides triggering is essential to landslide risk assessment. The Italian Alps have always been affected by shallow landslides and mud-debris flows, which caused considerable damage to property and, sometimes, casualties. We analysed information provided from different sources carrying on the most thorough research conducted for this alpine area. Thousands of documents and reports of rainfall values recorded over 80 years by rain gauges distributed in Sondrio and Brescia Provinces define the mean annual precipitation (MAP)-normalized intensity–duration thresholds for the initiation of shallow landslides and mud-debris flows. The established curves are generally lower compared to those proposed in literature for similar mountain areas in Italy and worldwide. Furthermore, we found that landslides occurred primarily at the same time or within 3 h from the maximum peak of rainfall intensity in summer events and in a period from 0 to 5 h or later in spring-autumn events. The paper provides a further contribution to the knowledge framework on the rainfall conditions required for the initiation of surficial landslides and mud-debris flows and their expected timing of occurrence. This knowledge is crucial to develop better warning strategies to mitigate geo-hydrological risk and reduce the socio-economic damage.

scholarly journals Debris-flow forecasting at regional scale by combining susceptibility mapping and radar rainfall

2015 ◽  
Vol 15 (3) ◽  
pp. 587-602 ◽  
Author(s):  
M. Berenguer ◽  
D. Sempere-Torres ◽  
M. Hürlimann
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Regional Scale ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Susceptibility Assessment ◽  
Radar Rainfall ◽  
Eastern Pyrenees ◽  
Rainfall Map ◽  
Rainfall Estimates

Abstract. This work presents a technique for debris-flow (DF) forecasting able to be used in the framework of DF early warning systems at regional scale. The developed system is applied at subbasin scale and is based on the concepts of fuzzy logic to combine two ingredients: (i) DF subbasin susceptibility assessment based on geomorphological variables and (ii) the magnitude of the rainfall situation as depicted from radar rainfall estimates. The output of the developed technique is a three-class warning ("low", "moderate" or "high") in each subbasin when a new radar rainfall map is available. The developed technique has been applied in a domain in the eastern Pyrenees (Spain) from May to October 2010. The warning level stayed "low" during the entire period in 20% of the subbasins, while in the most susceptible subbasins the warning level was at least "moderate" for up to 10 days. Quantitative evaluation of the warning level was possible in a subbasin where debris flows were monitored during the analysis period. The technique was able to identify the three events observed in the catchment (one debris flow and two hyperconcentrated flow events) and produced no false alarm.

scholarly journals Augmentation and Use of WRF-Hydro to Simulate Overland Flow- and Streamflow-Generated Debris Flow Hazards in Burn Scars

2021 ◽  
Author(s):  
Chuxuan Li ◽  
Alexander L. Handwerger ◽  
Jiali Wang ◽  
Wei Yu ◽  
Xiang Li ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Hydrological Modeling ◽  
Overland Flow ◽  
New Physics ◽  
Reanalysis Data ◽  
Peak Discharge ◽  
Burn Scar ◽  
Big Sur ◽  
Discharge Volume

Abstract. In steep wildfire-burned terrains, intense rainfall can produce large volumes of runoff that can trigger highly destructive debris flows. The ability to accurately characterize and forecast debris-flow hazards in burned terrains, however, remains limited. Here, we augment the Weather Research and Forecasting Hydrological modeling system (WRF-Hydro) to simulate both overland and channelized flows and assess postfire debris-flow hazards over a regional domain. We perform hindcast simulations using high-resolution weather radar-derived precipitation and reanalysis data to drive non-burned baseline and burn scar sensitivity experiments. Our simulations focus on January 2021 when an atmospheric river triggered numerous debris flows within a wildfire burn scar in Big Sur – one of which destroyed California’s famous Highway 1. Compared to the baseline, our burn scar simulation yields dramatic increases in total and peak discharge, and shorter lags between rainfall onset and peak discharge. At Rat Creek, where Highway 1 was destroyed, discharge volume increases eight-fold and peak discharge triples relative to the baseline. For all catchments within the burn scar, we find that the median catchment-area normalized discharge volume increases nine-fold after incorporating burn scar characteristics, while the 95th percentile volume increases 13-fold. Catchments with anomalously high hazard levels correspond well with post-event debris flow observations. Our results demonstrate that WRF-Hydro provides a compelling new physics-based tool to investigate and potentially forecast postfire hydrologic hazards at regional scales.

scholarly journals Evaluating methods for debris-flow prediction based on rainfall in an Alpine catchment

2021 ◽  
Vol 21 (9) ◽  
pp. 2773-2789
Author(s):  
Jacob Hirschberg ◽  
Alexandre Badoux ◽  
Brian W. McArdell ◽  
Elena Leonarduzzi ◽  
Peter Molnar
Keyword(s):  
Random Forest ◽  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Multiple Scales ◽  
Learning Algorithm ◽  
Predictive Performance ◽  
Early Warning Systems ◽  
Antecedent Rainfall ◽  
Data Set

Abstract. The prediction of debris flows is relevant because this type of natural hazard can pose a threat to humans and infrastructure. Debris-flow (and landslide) early warning systems often rely on rainfall intensity–duration (ID) thresholds. Multiple competing methods exist for the determination of such ID thresholds but have not been objectively and thoroughly compared at multiple scales, and a validation and uncertainty assessment is often missing in their formulation. As a consequence, updating, interpreting, generalizing and comparing rainfall thresholds is challenging. Using a 17-year record of rainfall and 67 debris flows in a Swiss Alpine catchment (Illgraben), we determined ID thresholds and associated uncertainties as a function of record duration. Furthermore, we compared two methods for rainfall definition based on linear regression and/or true-skill-statistic maximization. The main difference between these approaches and the well-known frequentist method is that non-triggering rainfall events were also considered for obtaining ID-threshold parameters. Depending on the method applied, the ID-threshold parameters and their uncertainties differed significantly. We found that 25 debris flows are sufficient to constrain uncertainties in ID-threshold parameters to ±30 % for our study site. We further demonstrated the change in predictive performance of the two methods if a regional landslide data set with a regional rainfall product was used instead of a local one with local rainfall measurements. Hence, an important finding is that the ideal method for ID-threshold determination depends on the available landslide and rainfall data sets. Furthermore, for the local data set we tested if the ID-threshold performance can be increased by considering other rainfall properties (e.g. antecedent rainfall, maximum intensity) in a multivariate statistical learning algorithm based on decision trees (random forest). The highest predictive power was reached when the peak 30 min rainfall intensity was added to the ID variables, while no improvement was achieved by considering antecedent rainfall for debris-flow predictions in Illgraben. Although the increase in predictive performance with the random forest model over the classical ID threshold was small, such a framework could be valuable for future studies if more predictors are available from measured or modelled data.

scholarly journals Characteristics of the Disastrous Debris Flow of Chediguan Gully in Yinxing Town, Sichuan Province, on August 20, 2019

2021 ◽  
Author(s):  
Li Ning ◽  
Tang Chuan ◽  
Zhang Xianzheng ◽  
Chang Ming ◽  
Shu Zhile ◽  
...  
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Warning System ◽  
Mitigation Measures ◽  
High Definition ◽  
Flood Peak ◽  
The Wenchuan Earthquake ◽  
Minjiang River ◽  
Monitoring And Early Warning

Abstract On August 20, 2019, at 2 a.m., a disastrous debris flow occurred in Chediguan gully in Yinxing town, China. The debris flow destroyed the drainage groove and the bridge at the exit of the gully. In addition, the debris flow temporarily blocked the Minjiang River during the flood peak, flooding the Taipingyi hydropower station 200 m upstream and leaving two plant workers missing. To further understand the activity of the debris flow after the Wenchuan earthquake, the characteristics of this debris flow event were studied. Eleven years after the Wenchuan earthquake, a disastrous debris flow still occurred in the Chediguan catchment, causing more severe losses than those of earlier debris flows. In this paper, the formation mechanism and dynamic characteristics of this debris flow event are analysed based on a drone survey, high-definition remote sensing interpretations and other means. The catastrophic debris flow event indicates that debris flows in the Wenchuan earthquake area are still active. A large amount of dredging work in the main gully could effectively reduce the debris flow risk in the gully. In addition, it is also important to repair or rebuild damaged mitigation measures and to establish a real-time monitoring and early warning system for the high-risk gully.

Sign in / Sign up

Export Citation Format

Share Document