Seismic characterization of clays blocks ruptures in a clayey landslide, the Harmaliere landslide.

2020 ◽  
Author(s):  
Sylvain Fiolleau ◽  
Denis Jongmans ◽  
Gregory Bièvre ◽  
Guillaume Chambon ◽  
Laurent Baillet
Keyword(s):  
Resonance Frequency ◽  
Environmental Parameters ◽  
Heavy Rain ◽  
Clay Material ◽  
Rain Event ◽  
Cumulative Number ◽  
Low Frequencies ◽  
Seismic Parameters ◽  
Seismic Characterization ◽  
Over Time

<p>Many regions of the world are exposed to landslides in clayey deposits, which pose major problems for land management and human safety. Clayey landslide activity is complex, showing a succession of periods of inactivity and reactivation phases that can evolve into sudden acceleration and catastrophic landslides and/or flows. Understanding the processes that control this activity therefore requires the continuous monitoring of specific parameters. At the end of June 2016, the Harmalière clayey landslide (located 30 km south of the city of Grenoble in the French Alps) was dramatically reactivated at the headscarp after 35 years of continuous but limited activity. The total volume involved, which moved in the form of tilted blocks of different sizes, was estimated at about 3,106 m3. Several sensors, including seismometers and GNSS stations, were installed immediately behind the main escarpment in early August 2016. They recorded a rupture involving a block of a few hundred cubic meters in November 2016. Additional data (seismology, meteorology, piezometer, etc.) were provided by a permanent observatory located a few hundred meters away in the nearby Avignonet landslide (RESIF2006). Two three-component seismic sensors were placed on the collapsed block and 10 meters aft on the stable part respectively.</p><p>Thus, four seismic parameters were monitored for 4 months until the clay block rupture: the cumulative number of microseisms, the resonance frequency of the block, the relative variation in Rayleigh wave velocity (dV/V) and the correlation coefficient (CC) in the range 1-12 Hz. All these parameters showed a significant precursor signal before the rupture, but at very different times. During the monitoring period, they also showed different responses to environmental parameters and in particular to precipitation. The resonance frequency increased slightly but steadily from 8 to 9 Hz (+12%) during the pre-break period, then decreased from 9 Hz to 7 Hz (-22%) just one hour before the break. However, the other three parameters showed significant variations a few weeks before failure. The dV/V and CC parameters reacted 1.5 month before the failure, during a very heavy rain event. The CC showed a general decrease over time, first affecting the high frequencies, then gradually spreading to the low frequencies. Finally, seismic activity is almost constant during the first three months, with only slight temporary increases during precipitation. One month before the rupture, a significant increase in the number of events is observed.</p><p>This study shows the potential of monitoring different seismic parameters over time in order to predict the slip of blocks in a clay material.</p>

scholarly journals Seismic characterization of a clay-block rupture in Harmalière landslide, French Western Alps

2020 ◽  
Vol 221 (3) ◽  
pp. 1777-1788 ◽  
Author(s):  
S Fiolleau ◽  
D Jongmans ◽  
G Bièvre ◽  
G Chambon ◽  
L Baillet ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Western Alps ◽  
Clay Material ◽  
Cumulative Number ◽  
Seismic Parameters ◽  
Seismic Characterization ◽  
Cross Correlations ◽  
The City ◽  
Rupture Mechanism

SUMMARY In late June 2016, the Harmalière clayey landslide (located 30 km south of the city of Grenoble, French Alps) was dramatically reactivated at the headscarp after a 35-yr-long period of continuous but limited activity. The total involved volume, which moved as sliding blocks of various sizes, was estimated to be about 2 × 10 6 m3. Two seismometers were installed at the rear of the main headscarp in August 2016, on both sides of a developing fracture delineating a block with a volume of a few hundred cubic metres. For 4 months, they continuously recorded seismic ambient vibrations and microearthquakes until the block broke. Five seismic parameters were derived from the monitoring: the cumulative number of microearthquakes (CNe), the seismic energy (SE), the block resonance frequency (fB), the relative variation in Rayleigh wave velocity (dV/V) deduced from noise cross-correlations between the two sensors and the associated correlation coefficient (CC). All parameters showed a significant precursory signal before the rupture, but at very different times, which indicates the complexity of the rupture mechanism in this clay material.

scholarly journals Statistics of seismicity to investigate the Campi Flegrei caldera unrest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Tramelli ◽  
C. Godano ◽  
P. Ricciolino ◽  
F. Giudicepietro ◽  
S. Caliro ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Central Area ◽  
Seismic Energy ◽  
Progressive Increase ◽  
Campi Flegrei ◽  
Cumulative Number ◽  
Seismic Parameters ◽  
Seismicity Rate ◽  
Seismic Catalogue ◽  
Vertical Ground

AbstractThe knowledge of the dynamic of the Campi Flegrei calderic system is a primary goal to mitigate the volcanic risk in one of the most densely populated volcanic areas in the world. From 1950 to 1990 Campi Flegrei suffered three bradyseismic crises with a total uplift of 4.3 m. After 20 years of subsidence, the uplift started again in 2005 accompained by a low increment of the seismicity rate. In 2012 an increment in the seismic energy release and a variation in the gas composition of the fumaroles of Solfatara (in the central area of the caldera) were recorded. Since then, a slow and progressive increase in phenomena continued until today. We analyze the INGV - Osservatorio Vesuviano seismic catalogue of Campi Flegrei from 2000 to 2020 in order to look for any variation in the seismic parameters and compare them with geochemical monitored ones. A remarkable correlation between independent variables of earthquake cumulative number, CO/CO2 values and vertical ground deformation reveals a likely common origin. Moreover the correlation between all the variables here analysed enlightens that the same origin can cause the temporal behavior of all these variables. We interpret the seismological, geochemical and geodetic observable in terms of the injection of magmatic fluids into the hydrothermal system or its pressurization.

A localised heavy rain event in Hong Kong

Weather ◽  
1998 ◽  
Vol 53 (8) ◽  
pp. 259-262
Author(s):  
C. C. Fu ◽  
C. C. Chan
Keyword(s):  
Hong Kong ◽  
Heavy Rain ◽  
Rain Event ◽  
Heavy Rain Event

scholarly journals Triple-Doppler radar analysis of the heavy rain event observed in the Lago Maggiore region during MAP IOP 2b

2003 ◽  
Vol 129 (588) ◽  
pp. 495-522 ◽  
Author(s):  
Jean-François Georgis ◽  
Frank Roux ◽  
Michel Chong ◽  
Stephanie Pradier
Keyword(s):  
Doppler Radar ◽  
Heavy Rain ◽  
Rain Event ◽  
Heavy Rain Event

The Heavy Rain Event of 29 October 2000 in Hana, Maui*

2005 ◽  
Vol 20 (4) ◽  
pp. 397-414 ◽  
Author(s):  
Ryan E. Lyman ◽  
Thomas A. Schroeder ◽  
Gary M. Barnes
Keyword(s):  
Heavy Rain ◽  
Rain Event ◽  
Low Level ◽  
Heavy Rain Event ◽  
Major Factors ◽  
Topographic Forcing

Abstract On 29 October 2000, the Hana region of Maui received 700 mm of rain in 7 h. Radar analyses revealed that the storm consisted of seven cells that were initiated along the southeast slope of Haleakala volcano. One of these cells survived for nearly 4 h and was responsible for 80% of the volumetric rainout from the storm. The interaction of low-level flow distorted by the island of Hawaii located farther east, the passage of a trough, and the topographic forcing caused by Haleakala volcano were major factors responsible for the evolution of the storm.

scholarly journals Lesson from the Heavy Rain Event of July 2018

2019 ◽  
Vol 37 (4) ◽  
pp. 366-368
Author(s):  
Hidenori MORITA
Keyword(s):  
Heavy Rain ◽  
Rain Event ◽  
Heavy Rain Event

scholarly journals Fibromyalgia Impact Reduction Using Online Personal Health Informatics: Longitudinal Observational Study

10.2196/15819 ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. e15819
Author(s):  
William Collinge ◽  
Robert Soltysik ◽  
Paul Yarnold
Keyword(s):  
Health Informatics ◽  
A Priori ◽  
Management Strategies ◽  
Personal Health ◽  
Single Subject ◽  
Cumulative Number ◽  
Impact Reduction ◽  
Health Diary ◽  
Over Time

Background Personal health informatics have the potential to help patients discover personalized health management strategies that influence outcomes. Fibromyalgia (FM) is a complex chronic illness requiring individualized strategies that may be informed by analysis of personal health informatics data. An online health diary program with dynamic feedback was developed to assist patients with FM in identifying symptom management strategies that predict their personal outcomes, and found reduced symptom levels associated with program use. Objective The aim of this study was to determine longitudinal associations between program use and functional impact of FM as measured by scores on a standardized assessment instrument, the Fibromyalgia Impact Questionnaire (FIQ). Methods Participants were self-identified as diagnosed with FM and recruited via online FM advocacy websites. Participants used an online health diary program (“SMARTLog”) to report symptom ratings, behaviors, and management strategies used. Based on single-subject analysis of the accumulated data over time, individualized recommendations (“SMARTProfile”) were then provided by the automated feedback program. Indices of program use comprised of cumulative numbers of SMARTLogs completed and SMARTProfiles received. Participants included in this analysis met a priori criteria of sufficient program use to generate SMARTProfiles (ie, ≥22 SMARTLogs completed). Users completed the FIQ at baseline and again each subsequent month of program use as follow-up data for analysis. Kendall tau-b, a nonparametric statistic that measures both the strength and direction of an ordinal association between two repeated measured variables, was computed between all included FIQ scores and both indices of program use for each subject at the time of each completed FIQ. Results A total of 76 users met the a priori use criteria. The mean baseline FIQ score was 61.6 (SD 14.7). There were 342 FIQ scores generated for longitudinal analysis via Kendall tau-b. Statistically significant inverse associations were found over time between FIQ scores and (1) the cumulative number of SMARTLogs completed (tau-b=–0.135, P<.001); and (2) the cumulative number of SMARTProfiles received (tau-b=–0.133, P<.001). Users who completed 61 or more SMARTLogs had mean follow-up scores of 49.9 (n=25, 33% of the sample), an 18.9% drop in FM impact. Users who generated 11 or more new SMARTProfiles had mean follow-up scores of 51.8 (n=23, 30% of the sample), a 15.9% drop. Conclusions Significant inverse associations were found between FIQ scores and both indices of program use, with FIQ scores declining as use increased. Based on established criteria for rating FM severity, the top one-third of users in terms of use had clinically significant reductions from “severe” to “moderate” FM impact. These findings underscore the value of self-management interventions with low burden, high usability, and high perceived relevance to the user. Trial Registration ClinicalTrials.gov NCT02515552; https://clinicaltrials.gov/ct2/show/NCT02515552

scholarly journals Export of <sup>134</sup>Cs and <sup>137</sup>Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

2013 ◽  
Vol 10 (2) ◽  
pp. 2767-2790 ◽  
Author(s):  
S. Nagao ◽  
M. Kanamori ◽  
S. Ochiai ◽  
S. Tomihara ◽  
K. Fukushi ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Heavy Rain ◽  
Rain Event ◽  
Normal Flow ◽  
Flow Conditions ◽  
Pulse Input ◽  
Heavy Rain Event ◽  
Coastal Marine ◽  
Rain Events ◽  
Heavy Rains

Abstract. Effects of a heavy rain event on radiocesium export were studied at stations on the Natsui River and the Same River in Fukushima Prefecture, Japan after Typhoon Roke during 21–22 September 2011, six months after the Fukushima Daiichi Nuclear Power Plant accident. Radioactivity of 134Cs and 137Cs in river waters was 0.011–0.098 Bq L−1 at normal flow conditions during July–September in 2011, but it increased to 0.85 Bq L−1 in high flow conditions by heavy rains occurring with the typhoon. The particulate fractions of 134Cs and 137Cs were 21–56% in the normal flow condition, but were close to 100% after the typhoon. These results indicate that the pulse input of radiocesium associated with suspended particles from land to coastal ocean occurred by the heavy rain event. Export flux of 134Cs and 137Cs by the heavy rain accounts for 30–50% of annual radiocesium flux in 2011. Results show that rain events are one factor controlling the transport and dispersion of radiocesium in river watersheds and coastal marine environments.

Impact of a severe rain event on C- and N-DBP precursor removal using IEX

2018 ◽  
Vol 18 (6) ◽  
pp. 2092-2099
Author(s):  
K. Doederer ◽  
Z. Ilieva ◽  
J. Keller
Keyword(s):  
Ion Exchange ◽  
Heavy Rain ◽  
Health Concern ◽  
Rain Event ◽  
Heavy Rain Event ◽  
Removal Capacity ◽  
C And N ◽  
Pre Treatment ◽  
Rain Events ◽  
Magnetic Ion

Abstract During disinfection, dissolved organic matter (DOM) is the major precursor to form disinfection by-products (DBPs), which may be of potential human health concern. Previous research focused on waters of continental climates and less on subtropical environments. However, water sources in subtropical climates are regularly impacted by major rain events during the summer months. This study evaluated the C- and N-DBP precursor removal capacity of two conventional ion exchange (IEX) resins and one magnetic ion exchange (MIEX) resin with a raw water at normal conditions and impacted by a heavy rain event. The rain event introduced 3 mg C/L total organic carbon (TOC) comprised mainly of low to medium molecular weight organics. All three resins were able to remove TOC and DBP precursors (&gt;66%) but being less efficient in reducing turbidity (3–48%) and colour (9–24%). The resin with the smallest bead size was affected the most by the increased medium MW DOM loading resulting in DOM and C-DBP precursor removal performance losses of 10% and 22%. When applied as a pre-treatment for coagulation, MIEX was more efficient in DBP precursor control than coagulation in addressing the additional organic and DBP precursor loading after a heavy rain event.

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