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The western Alpine belt is the focal point of moderate but constant seismic activity. Numerous geodynamic and seismological studies underline the many scientific questions linked to Alpine dynamic processes and the associated rate of deformation resulting from late continental collision phases, and the assessment of seismic hazard and its associated risks. Seismic monitoring in the northern French Alps was launched in 1987 with the installation of the first seismological network, hosted by the Earth Science Observatory at Grenoble Alpes University. Since then, the network has been updated over the years, keeping pace with technical developments in seismic instrumentation, monitoring and data management. The homogenization of information described in this scientific data paper is motivated by the need for a single instrumental seismic catalogue, consisting in arrival times picks and hypocenters using the same velocity model. The final catalogue SISMalp-1987–2023 (CC-BY-4.0) contains 50,822 weak-to-moderate earthquakes with local magnitude between −1.8 and 5.0; it can serve as a basis for all general seismotectonic and risk assessment studies in the region. [ABSTRACT FROM AUTHOR]

Deformation mechanisms of glaciers are highly sensitive to basal temperature; the motion of temperate glaciers is dominated by basal slip while cold‐based glaciers deform mainly by internal creep. While basal slip is usually aseismic, unstable slip sometimes occurs and can be detected by seismometers. I have detected clusters of repeating low‐frequency icequakes (LFIs) in the Mont‐Blanc massif. Some properties of LFIs are similar to the high‐frequency icequakes (HFIs) located at the base of Argentière glacier (Helmstetter, Nicolas, et al., 2015, https://doi.org/10.1002/2014jf003288). Both HFIs and LFIs occur as bursts of tens to several thousand events lasting for days or weeks, with typical inter‐event times of several minutes during bursts. Unlike HFIs that have a broad spectra, LFIs have a characteristic frequency of about 5 Hz at all stations, suggesting a rupture length of about 100 m. Seismic amplitudes and seismic waveforms of LFIs progressively evolve with time within each cluster, suggesting changes in either rupture length or rupture velocity. Most LFIs are detected during snowfall episodes while HFIs are not correlated with snowfall episodes. In this study, I used all available seismic stations within or around the Mont‐Blanc massif between 2017 and 2022. I found LFIs located all over the massif but mainly above 3,000 m. Some clusters are clearly associated with cold basal ice (near Mont‐Blanc summit) while others below 2,700 m a.s.l. are likely located under temperate glaciers and two clusters could be associated with landslides. This observation of LFIs on cold glaciers is consistent with laboratory friction experiments suggesting that cold ice promotes unstable slip (McCarthy et al., 2017, https://doi.org/10.1098/rsta.2015.0348; Saltiel et al., 2021, https://doi.org/10.1785/0220200480; Zoet et al., 2013, 2020, https://doi.org/10.1002/jgrf.20052, https://doi.org/10.1029/2020gl088964). Plain Language Summary: Glaciers flow due to slip at the base of the glacier and due to internal deformation. When the ice is at the melting point temperature, the presence of water at the base of the glacier promotes basal slip, while for cold ice (below melting temperature) the glacier is stuck to its bed and most deformation occurs within the glacier. The displacement of the glacier is usually slow and continuous, but in some cases slip can occur as intermittent fast slip events. These "icequakes" generate ground vibrations that can be recorded by seismic sensors. In this study, I analyze clusters of icequakes that repeat more or less regularly with time every few minutes, with progressive changes in amplitudes and inter‐event times. The signals have a narrow spectrum with a main frequency of about 5 Hz that suggests a rupture length of about 100 m. These events mainly occur during snowfall episodes and are mostly located on glaciers above 3,000 m. At these locations, the ice is often colder than the melting point temperature. These repeating icequakes are probably associated with unstable slip at the base of glaciers. This result is surprising since basal motion for cold ice (below melting point) is believed to be negligible, but it is however consistent with laboratory experiments suggesting that unstable slip is promoted by cold temperatures. A few events occur on or close to glaciers at lower elevations, where ice is at the melting point temperature. They may be associated with basal glacier motion or with landslides induced by glacier retreat. Key Points: I detected low frequency icequake signals with a main frequency of 5 Hz that repeat every few minutesLow frequency icequakes mainly occur during and after snowfall episodesThey are located on several glaciers of the Mont‐Blanc massif mainly above 3,000 m a.s.l. where the basal ice is possibly cold [ABSTRACT FROM AUTHOR]

Between August 2017 and March 2019, an intense seismic swarm was recorded in the Maurienne valley in the north of the Belledonne massif (Western French Alps). In order to study the spatiotemporal evolution of the Maurienne swarm, we created a high‐resolution catalog based on template matching, double‐difference relocation, and moment magnitudes. The catalog includes 71,064 events with a maximum moment magnitude of 3.5 and a magnitude of completeness of 0.7. The seismic activity is interpreted as the reactivation of an N80 strike‐slip fault system called Fond de France. Moreover, earthquake relocation reveals the presence of a shallower fault system with the same strike, but opposite dip direction and smaller size. The presence of two distinct fault systems may explain the observed variation of the b‐value with depth. The seismicity migrated asymmetrically in all directions during the course of about 15 months. Shorter migrations lasting 2–3 days are also observed. The different migration patterns suggest that the swarm is driven by several mechanisms, possibly pore‐pressure diffusion, aseismic slip, and earthquake interactions. Key Points: We use template matching, double‐difference relocations, and moment magnitudes to create a high‐resolution catalog of the Maurienne swarmAt least two conjugate fault systems with opposite dip directions were reactivated during the swarmThe complex migration of seismicity suggests that the swarm may be driven both by pore‐pressure diffusion and by earthquake interactions [ABSTRACT FROM AUTHOR]

High mountain environments are increasingly affected by rockfall‐related hazards, driven by climate change. Studying rockfall in these environments is, however, challenging due to the inaccessibility of mountain ridges and the complex interaction between controlling factors. In this study, the rock wall of Grosse Grabe North Pillar in the Matter valley (Western Swiss Alps) was studied in detail over a timespan of 4 years (2017–2021). Data was collected from time‐lapse photography, terrestrial laser scanning, unmanned aerial vehicle photogrammetry and seismic measurements. The presented dataset is unique because data collection started before the onset of the rock wall destabilization, allowing us to understand precursory indicators of large‐scale events. In total, we recorded 382 rock‐ and cliff fall events (100–31 300 m3), with a total volume of 204 323 ± 8173 m3, resulting in a scar depth of ~40 m. An associated rock wall retreat rate of 71.2 ± 2.8 mm year−1 was calculated for the 1991–2021 period. Highly fractured south‐exposed gneiss lithology is viewed as the main predisposition for the observed rock‐ and cliff fall events, allowing high‐temperature oscillations to cause irreversible movements at fracture level. Cliff falls (104–106 m3) were preluded by an outward movement of the rock wall that started to increase 1.5 years before any significant collapse of the rock wall, reaching locally up to 30 cm. All cliff fall events occurred in summer, exposing ice in the clefts. This is assumed to be the base of the permafrost from the north side. Rapid permafrost degradation is viewed as a triggering factor after its exposure, causing progressive failure of the rock wall, leading to very high rock wall retreat rates on a decadal timescale. [ABSTRACT FROM AUTHOR]

The mass transfer mechanisms in landslides are complex to monitor because of their suddenness and spatial coverage. The active clayey Harmalière landslide, located 30 km south of Grenoble in the French Alps, exhibits two types of behavior: in its upper part, decameter-sized clay blocks slide along a listric slip surface, while a flow-like mechanism is observed in a clayey remolded material a few hundred meters below the headscarp. The landslide underwent a major retrogression affecting 45 ha in March 1981 and has experienced multiple reactivations since then. The last major event took place on the 26th of June 2016, and a large investigation survey was conducted to better understand the reactivation mechanism. A multi-method investigation was carried out at different temporal and spatial scales, including aerial photograph and light detection and ranging processing, correlation of optical satellite images, global navigation satellite system monitoring, continuous seismic monitoring, and passive seismic survey. The morphological evolution of the landslide was traced over the last 70 years, showing a headscarp retrogression of 700 m during multiple reactivations and a total mass transfer of more than 6 × 106 m3. The detailed study of the 2016 event allowed to track and understand the mechanism of a mass transfer of 1 × 106 m3 in 5 weeks, from a sliding mechanism at the headscarp to an earthflow at the toe. [ABSTRACT FROM AUTHOR]

Among mountainous permafrost landforms, rock glaciers are mostly abundant in periglacial areas, as tongue-shaped heterogeneous bodies. Passive seismic monitoring systems have the potential to provide continuous recordings sensitive to hydro-mechanical parameters of the subsurface. Two active rock glaciers located in the Alps (Gugla, Switzerland, and Laurichard, France) have been instrumented with seismic networks. Here, we analyze the spectral content of ambient noise to study the modal sensitivity of rock glaciers, which is directly linked to the system's elastic properties. For both sites, we succeed in tracking and monitoring resonance frequencies of specific vibrating modes of the rock glaciers over several years. These frequencies show a seasonal pattern characterized by higher frequencies at the end of winters and lower frequencies in warm periods. We interpret these variations as the effect of the seasonal freeze–thawing cycle on elastic properties of the medium. To assess this assumption, we model both rock glaciers in summer, using seismic velocities constrained by active seismic acquisitions, while bedrock depth is constrained by ground-penetrating radar surveys. The variations in elastic properties occurring in winter due to freezing were taken into account thanks to a three-phase Biot–Gassmann poroelastic model, where the rock glacier is considered a mixture of a solid porous matrix and pores filled by water or ice. Assuming rock glaciers to be vibrating structures, we numerically compute the modal response of such mechanical models by a finite-element method. The resulting modeled resonance frequencies fit well the measured ones over seasons, reinforcing the validity of our poroelastic approach. This seismic monitoring allows then a better understanding of the location, intensity and timing of freeze–thawing cycles affecting rock glaciers. [ABSTRACT FROM AUTHOR]

A network of seismometers has been installed on the Gugla rock glacier since October 2015 to estimate seismic velocity changes and detect microseismicity. These two processes are related to mechanical and structural variations occurring within the rock glacier. Seismic monitoring thus allows a better understanding of the dynamics of rock glaciers throughout the year. We observed seasonal variations in seismic wave velocity and microseismic activity over the 3 yr of the study. In the first part of our analysis, we used ambient noise correlations to compute daily changes of surface wave velocity. In winter, seismic wave velocities were higher, probably due to refreezing of the permafrost active layer and cooling of the uppermost permafrost layers, leading to increased overall rigidity of the medium. This assumption was verified using a seismic model of wave propagation that estimates the depth of P - and S -wave velocity changes from 0 down to 10 m. During melting periods, both a sudden velocity decrease and a decorrelation of the seismic responses were observed. These effects can probably be explained by the increased water content of the active layer. In the second part of our study, we focused on detecting microseismic signals generated in and around the rock glacier. This seismic activity (microquakes and rockfalls) also exhibits seasonal variations, with a maximum in spring and summer, which correlates principally with an exacerbated post-winter erosional phase of the front and a faster rock glacier displacement rate. In addition, we observed short bursts of microseismicity, both during snowfall and during rapid melting periods, probably due to pore pressure increase. [ABSTRACT FROM AUTHOR]

The upper part of the Ubaye Valley (French Alps) is characterized by alternating mainshock‐aftershock sequences and swarms. Particularly, during the 2012–2015 crisis, four mainshocks with Ml > 3.5 occurred. We here focus on the aftershocks of the largest one (Ml = 4.8, 7 April 2014), in order to better understand the involved processes behind this peculiar seismic behavior. We use template matching detection, waveform classification, and double‐difference relocations to analyze this seismicity, on average and at the scale of the clusters that compose it. Most event sources are aligned along a plane consistent with the mainshock fault (N165, 65°W), but occurred on conjugate structures. A few clusters of seismicity are also observed far from the mainshock source. Our analysis shows that distinct, spatially separated processes are at play. While coseismic stress transfer explains the seismicity close to the mainshock source, fluid‐pressure diffusion and distant stress triggering are required to generate events farther away. The overall distributions in time and magnitude followed a slow Omori's decay and a Gutenberg‐Richter relationship, respectively. However, these classical responses arise from the superposition of very different behaviors, associated with different processes at depth. Plain Language Summary: Earthquakes have regularly shaken the upper part of the Ubaye valley, near the town of Barcelonnette in the Southwestern French Alps, for nearly 20 years. The earthquake behavior is peculiar, as swarms of numerous low magnitude events alternate with larger earthquakes, such as the Ml 4.8 one occurring on 7 April 2014. To understand this dual behavior, we performed an in‐depth analysis of the aftershock of this event. The seismicity mainly aligns on a plane consistent with the mainshock fault (N165, 65°W). However, most of the events occurred on branching structures, belonging to the damaged zone of this fault, or on some other small faults far away. While the average behavior of this aftershock sequence is close to a standard one, we show that two different processes occurred at depth. Events occurring close to the mainshock are triggered by coseismic stress transfer, while fluid‐pressure diffusion are likely required to explain the seismicity further away. Such dual process should be considered for seismic hazard assessment. Key Points: Improved detection, classification, and location of the aftershock sequence following the Ml 4.8 earthquake in the French AlpsEvent sources align consistently along the mainshock fault, but on structures of its damaged zone or to small faults further awaySpatial separation of two different processes: coseismic stress transfer close to the mainshock and fluid‐pressure diffusion further away [ABSTRACT FROM AUTHOR]

Probabilistic seismic hazard models (PSHM) are used for quantifying the seismic hazard at a site or a grid of sites. In this study, a methodology is proposed to compare the distribution of the expected number of sites with exceedance with the observed number considering an acceleration threshold at a set of recording sites. The method is applied to France and Turkey. The French accelerometric database is checked to produce a reliable accelerometric data set. In addition, we also used a synthetic data set inferred from an instrumental catalogue combined with a ground-motion prediction equation. The results show that the MEDD2002 and AFPS2006 PSH models overestimate the number of sites with exceedance for low acceleration levels (below 40 cm s−2) or short return periods (smaller than 50 yr for AFPS2006 and 475 yr for MEDD2002). For larger acceleration levels, there are few observations and none of the models is rejected. In Turkey, the SHARE hazard estimates can be tested against ground-motion levels of interest in earthquake engineering. As the completeness issue is crucial, the recorded data at each station is analysed to detect potential gaps in the recording. As most accelerometric stations are located on soil, accelerations at rock are estimated using a site-amplification model. Different minimum intersite distances and station configurations are considered. The observed numbers of sites with exceedance are well within the bounds of the predicted distribution for accelerations between 103 and 397 cm s−2. For higher levels, both the observed number and the predicted percentile 2.5 are zero, and no conclusion can be drawn. [ABSTRACT FROM AUTHOR]

This work focuses on the characterization of seismic sources observed in clay–shale landslides. Two landslides are considered: Super-Sauze (France) and Valoria (Italy). The two landslides are developed in reworked clay–shales but differ in terms of dimensions and displacement rates. Thousands of seismic signals have been identified by a small seismic array in spite of the high-seismic attenuation of the material. Several detection methods are tested. A semi-automatic detection method is validated by the comparison with a manual detection. Seismic signals are classified in three groups based on the frequency content, the apparent velocity and the differentiation of P and S waves. It is supposed that the first group of seismic signals is associated to shearing or fracture events within the landslide bodies, while the second group may correspond to rockfalls or debris flows. A last group corresponds to external earthquakes. Seismic sources are located with an automatic beam-forming location method. Sources are clustered in several parts of the landslide in agreement with geomorphological observations. We found that the rate of rockfall and fracture events increases after periods of heavy rainfall or snowmelt. The rate of microseismicity and rockfall activity is also positively correlated with landslide displacement rates. External earthquakes did not influence the microseismic activity or the landslide movement, probably because the earthquake ground motion was too weak to trigger landslide events during the observation periods. [ABSTRACT FROM AUTHOR]

In children conventional hemodialysis does not often improve growth. We determined linear growth in five children on in-center intensified and daily hemodialysis (IDd) regimen, with a mean age of 8 years 7 months at enrolment. Four of five were on growth hormone started for a median of 28.5 months before IDd. IDd was delivered 5 to 6 times weekly, for three hours each session. Mean follow up of IDd was 18.6 months. Dropout from IDd was kidney transplantation ( n=4) or transfer to another center ( n=1). IDd and free diet improved appetite, thereby protein intake, was above 2 g/kg/BW. Median weekly Kt/Vurea was 9.1 (8.7 to 10.4). Predialysis phosphorus blood levels were higher at the start (2.04±0.34 mmol/L) than at end of IDd (1.39±0.41 mmol/L) without need for carbonate of calcium in four of five cases. During conventional dialysis ht SDS decreased from −0.8 to −1.44, which occurred predominantly before rhGH start. Conversion to IDd significantly increased growth velocity to a mean of 13 cm/year (10.3–18) with a mean change of +1.84 ht SDS/year (0.4 to 2.7). This preliminary report suggests the potential efficacy of IDd regimen in promising growth velocity, either directly from a higher dialysis dose or indirectly through an improved nutritional status. [ABSTRACT FROM AUTHOR]