The unstable rock slope "Spitze Stei" (Kandersteg, Switzerland) has shown significantly increased activity for several years. Since 2018, observed displacement rates can exceed 40 cm per day seasonally. The instability covers a total area of ​​approximately half a square km. The volume of the moving rock and debris mass is ~16 million m3, distributed across several rock compartments. Driven by degrading permafrost and enhanced gliding planes, these primary gravitational instabilities result in secondary, often destructive, debris flows into the Oeschibach channel. While continuous monitoring is essential for risk management, traditional visual and radar methods are often constrained by adverse weather conditions, limited temporal resolution and limited sensitivity to subsurface processes. To overcome these limitations and monitor rockslide internal deformation, material damage, and ongoing mass-movement processes at high spatial resolution, a dense temporary seismic network consisting of 64 SmartSolo nodes (natural frequency 5 Hz) were deployed across the slope at the end of June 2025 and operated for nearly three months. This dataset is complemented by recordings from three semi-permanent seismometers that have been operating since October 2021, providing a longer-term reference for background seismicity and site-specific noise characteristics.We analyze the continuous seismic records to detect and characterize signals from a variety of mass-movement phenomena, including rockfalls, granular flows, debris flows and avalanche-related activity. Signals are evaluated based on waveform properties, duration, amplitude evolution, and spectral content, with comparisons across sensor types and periods. A key objective is to isolate and cluster internal microseismic activity, distinguishing it from background noise, external sources (e.g., icequakes), and transient permafrost-related signals.Our preliminary results highlight a diverse set of seismic signal types linked to both surface processes and internal rockslide dynamics. This observed variability suggests changes in deformation style across different rock compartments, demonstrating the potential of dense nodal seismic arrays to resolve internal rockslide processes relevant for hazard monitoring.

Abstract Haiti regularly experiences destructive earthquakes, but seismic monitoring in the region has historically been limited. Recent deployments of citizen-hosted RaspberryShake seismometers and temporary seismic deployment following the 2021 Mw 7.2 earthquake provide new data to study the region’s seismotectonics. However, high noise levels at many stations, in particular the RaspberryShake ones, limit detection, hence the fault imaging capability of these instruments. This study explores the use of a Deep Learning denoising algorithm, DeepDenoiser, to improve their seismic signal and earthquake detection capabilities. We find that DeepDenoiser raises the average signal-to-noise ratio of seismic signals by 4.7 dB and increases earthquake detections, but also raises false detections when using short-term average/long-term average and deep learning detection methods. Template matching, however, when combined with DeepDenoiser, yields more true detections and fewer false detections than traditional band-pass-filtered waveforms. This suggests that DeepDenoiser is better suited for retrospective studies than for real-time applications. Using DeepDenoiser and template matching, we compile a 2 yr, high-resolution earthquake catalog for Haiti containing about three times the number of events of the original catalog. The improved catalog furthers our understanding of the 2021 Mw 7.2 earthquake sequence, highlighting particularly clearly the segmented nature of the aftershock distribution with a generally northeast-dipping cluster in the east that coincides with the hypocenter and first reverse phase of the rupture, and a series of aftershocks farther west that coincide with the mostly strike-slip phase of the rupture. The improved catalog also reveals potentially fluid-induced offshore seismic swarms in the Jérémie basin and active seismicity below Lake Enriquillo in the Dominican Republic. This catalog advances our understanding of the region’s seismicity and provides further opportunities to study the larger regional tectonic context.

On 14 August 2021, the Southern Peninsula of Haiti experienced a Mw7.2 earthquake, 15 years after the devastating Mw7.0 event that struck the capital city of Port-au-Prince on 12 January 2010. We use the data from a local temporary broadband seismic network, a national network of low-cost seismometers, and regional seismic networks, together with a probabilistic, global-search, non-linear location method (NLL-SSSTcoherence), to obtain a catalog of 5341 precisely relocated events spanning 20 August 2021 to 6 February 2022, with local magnitudes ranging from 0.5 to 5.6. We compute focal mechanisms for a subset of 73 events through waveform inversion. The catalog can be split into aftershocks directly related to the Nippes earthquake rupture process, and two off-rupture clusters. A first one concerns the Anse-& agrave;-Veau-Mirago & acirc;ne area and corresponds mostly to the aftershock sequence of two Mw 5.3 and 4.9 earthquakes that likely activated a segment of the offshore, south-dipping, J & eacute;r & eacute;mie-Malpasse reverse fault system. A second sequence, offshore J & eacute;r & eacute;mie and clustered close to the offshore trace of that same fault, started immediately after the Nippes mainshock and continued during the entire time interval of the present study. The swarm-like temporal distribution of this sequence, as well as evidence for directional propagation of the epicenters, indicate that it was likely driven by fluid migration. We interpret this seismicity as the result of oblique sub-crustal slip on a south-dipping fault which accounts for oblique convergence between the Gon & acirc;ve and Caribbean plates in southern Hispaniola. Strain in the crust then partitions between reverse faulting on the J & eacute;r & eacute;mie-Malpasse fault system, strike-slip on the Enriquillo fault, and hybrid faulting in between. Seismic hazard assessment for the region should therefore account for faults other than the Enriquillo fault as potential sources for future earthquakes.

We present a joint analysis of all available seismological, geodetic and geological data to assess seismic hazard along the vulnerable French-Italian Riviera. This is achieved by discussing the most likely scenario and quantifying recurrence times for strong earthquakes. The most destructive earthquake known in the area (1887, M-w similar to 6.8) occurred offshore on the Ligurian Fault. This event is typical of strong but sporadic earthquakes that can provide valuable insights into the behavior of low-slip-rate faults. Given the uncertainties on each type of data, the results of the different approaches indicate a wide range of recurrence times for such an earthquake, from 607 to 15,969 yr. Considering the most probable values refines this range to 2353-9484 yr. Variations in seismicity rate associated with changes in geodynamic and environmental conditions are also discussed. Since the 1887 earthquake only ruptured the central part of the Ligurian Fault, the largest future hazard is posed by the adjacent fault segments, which could generate an event of similar magnitude.

Recent developments in Distributed Acoustic Sensing (DAS) have greatly expanded our capabilities for dense geophysical instrumentation by tapping into existing (but unused) fibre-optic telecommunication networks. Leveraging these so-called "dark fibres" permits an extremely rapid deployment of thousands of vibration sensors over distances of several tens of kilometres, which is ideal for rapid postseismic response efforts. Here we report on the use of dark-fibre DAS for monitoring of the aftershock sequence of the 2019-11-11 Mw 4.9 Le Teil, France earthquake. Through comparison with the local seismometer network, we assess the capabilities of the DAS array to detect and locate small-magnitude seismic events. Likely owing to cable deployment and DAS sensing characteristics, we find that the DAS noise floor is up to 3 orders of magnitude higher than that of nearby seismometers, which greatly inhibits the detection and analysis of the low-energy events. However, locating a selected aftershock with DAS yields an accuracy and precision that is comparable to that of the seismic network, even though the DAS array has a relatively unfavourable geometry. Based on these observations we provide a number of recommendations for routinely incorporating DAS into postseismic response protocols, and for optimal use of DAS alongside conventional seismic instrumentation.

The spatial distribution of seismicity in active fault zones depends primarily on the geometry of the fault networks. However, recent advances suggest that seismic activity may also be controlled by the rheology of the geological units surrounding fault zones. In the present work, we use seismological and geological analyses to investigate the influence of the local geology on the rupture nucleation and propagation of the 2019 Le Teil earthquake (France; ML = 5.4; Mw = 4.9) and on the distribution of its aftershocks. The kinematic rupture model of the mainshock, obtained by joint inversion of seismological and INSAR data, shows that the rupture nucleated at 1 km depth and propagated mainly up-dip and bilaterally. Template matching detection identifies 115 aftershocks (-1.6 <= ML <= 2.5) in the two months following the mainshock. Double difference location shows that the aftershocks delineate a 4 km-long NE-SW plane with a 60 degrees dip to the SE, consistent with the extent and the geometry of the La Rouvi & egrave;re fault activated during the mainshock. By placing the seismicity in the local geological context, we conclude that the seismic activity was largely controlled by the rheological properties of the contrasting lithology. The mainshock nucleated in marly-limestone, but the coseismic slip was maximum above 0.6 km depth in a massive limestone more prompt to store elastic strain. The aftershocks occurred mainly in marls and marly limestone. They are interpreted as ruptures in competent beds of limestones of varying thickness, interbedded with marls.

The largest magnitude strike-slip event of the instrumental seismology era along the northern Caribbean plate boundary, with a moment magnitude of 7.7, occurred on 28 January 2020 on the Oriente transform fault, along the northern edge of the Cayman Trough, west of Cuba. We use local, regional, and global seismic waveforms and coseismic geodetic offsets, to produce high-resolution rupture models for both the low-frequency (~ 0.02 Hz) and high-frequency (~ 1 Hz) components of the rupture using a finite fault kinematic inversion and back-projection imaging, respectively. We document a rupture that propagated predominantly unilaterally westward, with an initial phase at subshear speed for 20–-30~s and over 40 to 50~km, followed by an acceleration to supershear speed that persisted all the way to the western end of the rupture, for 40~s and over about 200~km. Supershear rupture speed is consistent with strong motion observations of low ground acceleration levels in the near-field of the fault and low aftershock production in numbers and moment release. The rupture followed a very linear, unsegmented portion of the Oriente fault that had not experienced significant seismic activity for at least a century. Observational evidence and models indicate that the 28 January 2020, Mw7.7 earthquake, supershear over most of its length, had a smooth rupture process along a simple linear fault segment where earthquake nucleation is infrequent and interseismic locking depth shallow, two characteristics that may explain this unusually large magnitude supershear event.

While the triggering process of landslides remains are multiple, the importance of seismic waves is well established. The leading approach to study coseismic landslides is through statistical studies or simple models such as the Newmark method. While providing useful information, these approaches fall short at predicting landslide triggering especially in complex environments such as submarine conditions. Here we study the possibility to establish a simple physically-based model to fulfill this purpose. Assuming strain is localized in a thin weak layer at the base of the landslide, we model the landslide as slip on a planar sloping surface. By analogy to tectonic faults, we adopt the rate-and-state friction law on this surface, a phenomenological law widely used to describe slow sliding on faults during earthquakes. This approach produces a range of landslide behaviors ranging from stable and unstable conditions. With a one-dimensional mathematical and numerical model, representing a wave incidence normal to the landslide interface, we identify the main triggering factors of slow and fast sliding and characterize the non-linear evolution of the slip instability. In particular, we map the range of slip behaviors as a function of non-dimensional numbers, such as the ratio of incident wave frequency to seismic resonance frequency of the layer. The incident wave amplitude also play an important role in the model: the slip velocity during acceleration depends exponentially on the ratio of the incident stress wave amplitude to the ambient confining stress. This basic model is a starting point that can be extended to include other relevant processes like the coupling between pore pressure and slip.

&lt;p&gt;On August 2021, 14&lt;sup&gt;th&lt;/sup&gt;, a Mw 7.2 earthquake struck Haiti&amp;#8217;s southern peninsula, eleven years after the devastating Mw 7 January 12, 2010 earthquake that occurred near Port au Prince. This large event, called the Nippes earthquake, has been recorded locally by the citizen network composed of low-cost raspberry shake stations. A precise analysis of the mainshock rupture from geodetic and seismic data revealed both left lateral strike slip and trust motion.&lt;/p&gt; &lt;p&gt;Few days after the mainshock, a temporary network consisting of 12 broadband stations was deployed in the vicinity of the epicentral zone in order to better record the aftershock sequence. Data from August 20 to December 31, 2021, were used to determine a suitable 1D velocity model of the zone and relocate about 2500 aftershocks that highlight the activation of several structures.&lt;/p&gt; &lt;p&gt;In this study, we focus our analysis on the region of Mirago&amp;#226;ne situated between the ruptures of the 2021 and the 2010 earthquakes. &amp;#160;Before the Nippes earthquake, only a few events were detected there. Then, the Nippes earthquake triggered a burst of seismicity that lasted two months and stopped on November 2, 2021 and resumed in January 14 until March 10, 2022 with the occurrence on January 24th of two earthquakes in less than an hour of magnitude 5.3 and 5.1 respectively. We use the new 1D velocity model and the NonLinLoc using Source-Specific Station Term Corrections method&lt;strong&gt; &lt;/strong&gt;(NLL-SSST) to relocate this seismic sequence. We find that the two larger earthquakes of magnitude slightly greater than 5 are closely located and confirm their reverse faulting mechanism using the waveform inversion method FMNEAR. The relocated seismicity is distributed from the surface to 20 km deep between the coast and the Enriquillo left-lateral strike-slip fault and along a plane which dips southward at ~50&amp;#176;, in agreement with the reverse faulting mechanism of the two larger magnitude &gt; 5 earthquakes.&lt;/p&gt;

SUMMARY In 1906, an earthquake with a magnitude estimated between Mw 8.4 and 8.8 occurred in the subduction zone along the coast of Ecuador and Colombia. This earthquake caused extensive damage on the coast but had a rather small impact on the capital city of Quito, situated 180 km away. At that time, the city of Quito extended over a small area with a few thousand inhabitants, while today it stretches over 40 km and has a population of over 3 million, with most of the city built without paraseismic regulations. The aim of this study is to obtain new insights on the impact that large earthquakes from the subduction zone would have on the city today. This question is crucial since we know that the city of Quito is prone to site effects and that the southern part of the city amplifies seismic waves at low frequencies, around 0.3–0.4 Hz. In April 2016, an Mw 7.8 earthquake occurred on the subduction interface in the Pedernales area. This event was the first large earthquake in the city of Quito to be well recorded by 13 stations of the permanent accelerometric network (RENAC). In this study, we take advantage of this data set (main shock and large aftershock recordings) to (1) test an empirical Green's function blind simulation approach where the input stress drop is taken from a global catalogue of source time functions, (2) compare the synthetic accelerograms and ground motion values we obtain for an Mw 7.8 earthquake with the actual recordings of the Pedernales earthquake and then (3) simulate larger earthquakes of Mw 8.2 and 8.5 from the subduction zone. For Mw 7.8 simulations, our approach allows a good reproduction of the ground motions in the whole frequency bands and properly takes into account site effects. For Mw 8.2 and 8.5 simulations, we obtain for the stations in the southern part of the basin, larger values at low frequencies than the predicted motion given by ground motion models. These values, although high, should be supported by new or recent buildings if they are constructed respecting the building code that applies in Quito. Therefore, for this type of strong but distant earthquake, the seismic standards appear to be well suited and it is imperative to ensure that they are well considered in the design of the new buildings to be constructed, especially in the southern part of the expanding city.

ABSTRACT The 14 August 2021 Mw 7.2 Haiti earthquake struck 11 yr after the devastating 2010 event within the Enriquillo Plantain Garden (EPG) fault zone in the Southern peninsula of Haiti. Space geodetic results show that the rupture is composed of both left-lateral strike-slip and thrust motion, similar to the 2010 rupture; but aftershock locations from a local short-period network are too diffuse to precisely delineate the segments that participated in this rupture. A few days after the mainshocks, we installed 12 broadband stations in the epicentral area. Here, we use data from those stations in combination with four local Raspberry Shakes stations that were already in place as part of a citizen seismology experiment to precisely relocate 2528 aftershocks from August to December 2021, and derive 1D P- and S-crustal velocity models for this region. We show that the aftershocks delineate three north-dipping structures with different strikes, located to the north of the EPG fault. In addition, two smaller aftershock clusters occurred on the EPG fault near the hypocenter area, indicative of triggered seismicity. Focal mechanisms are in agreement with coseismic slip inversion from Interferometric Synthetic Aperture Radar data with nodal planes that are consistent with the transpressional structures illustrated by the aftershock zones.

. On November 11, 2019, a M w 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE–SW La Rouvière normal fault in reverse faulting in agreement with the present-day E–W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitorthetemporalandspatialevolutionofmicroearthquakesclosetothefaultplaneandtemporal evolutionoftheseismicresponseof3damagedhistoricalbuildings,andtostudysuspectedsitee ff ects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by di ff erent institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakesalongthemajorregionalCévennefaultsysteminacontextofpresent-daycompressional tectonics.

On 2 October 2020, the Maritime Alps in southern France were struck by the devastating Storm Alex, which caused locally more than 600 mm of rain in less than 24 h. The extreme rainfall and flooding destroyed regional rain and stream gauges. That hinders our understanding of the spatial and temporal dynamics of rainfall–runoff processes during the storm. Here, we show that seismological observations from permanent seismic stations constrain these processes at a catchment scale. The analysis of seismic power, peak frequency, and the back azimuth provides us with the timing and velocity of the propagation of flash-flood waves associated with bedload-dominated phases of the flood on the Vésubie River. Moreover, the combined short-term average to long-term average ratio and template-matching earthquake detection reveal that 114 local earthquakes between local magnitude ML=-0.5 and ML=2 were triggered by the hydrological loading and/or the resulting in situ underground pore pressure increase. This study shows the impact of Storm Alex on the Earth's surface and deep-layer processes and paves the way for future works that can reveal further details of these processes.

On 14 August 2021, the moment magnitude (M-w) 7.2 Nippes earthquake in Haiti occurred within the same fault zone as its devastating 2010 M-w 7.0 predecessor, but struck the country when field access was limited by insecurity and conventional seismometers from the national network were inoperative. A network of citizen seismometers installed in 2019 provided near-field data critical to rapidly understand the mechanism of the mainshock and monitor its aftershock sequence. Their real-time data defined two aftershock clusters that coincide with two areas of coseismic slip derived from inversions of conventional seismological and geodetic data. Machine learning applied to data from the citizen seismometer closest to the mainshock allows us to forecast aftershocks as accurately as with the network-derived catalog. This shows the utility of citizen science contributing to our understanding of a major earthquake.

&lt;p&gt;On January 12th 2010, Haiti was hit by one of the largest seismic disasters known to date. At the time, seismic sensors, knowledge and risk culture were critically lacking. The dramatic social, political and economic consequences of the event revealed the importance of developing seismic risk reduction in Haiti.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;We present here the communication components of a citizen-seismology project in Haiti.. The project called OSMOSE propose to contribute to risk reduction by in installing low-cost seismic sensors (Raspberry Shake) at volunteers&amp;#8217; houses to (1) collect seismic data and complement the national seismic network, and (2) engage with the population to understand their risk perception and the usage they could make of these tools.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;An international team of geoscientists, education specialists and social science researchers gathered to build an efficient communication strategy, which aimed at (1) informing the public about seismic risk and felt earthquakes, (2) establish a trust relationship with volunteers who host sensors, educate them about science and risk, (3) support the volunteers in their ambassador roles among their community.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;In order to establish a communication strategy that was inclusive and suitable to the local cultural context (including scientific literacy level, vodou culture, risk culture, past trauma, trust in the authorities etc), we first led a quantitative survey among the general public and a series of sociological semi-structured interviews with Raspberry Shake hosts who volunteered for the project. This enabled us to assess information expectations in terms of content and medium.&amp;#160;&lt;/p&gt;&lt;p&gt;Working with geoscientists, we then designed a first set of tools to respond to these needs, when possible. For instance, a website (https://ayiti.unice.fr/ayiti-seismes/) enables the public to know in a few minutes where an earthquake occurs and what its magnitude is, thanks to seismic data collected by the citizen network. It also displays educational information about seismology. The LastQuake app which crowdsources seismic data was translated into Creole for better access in the country. Finally, a WhatsApp group gathering volunteers and scientists has also been created given the importance of the messaging app in daily communication and information practices in Haiti. The group enables them to exchange information about the technical and scientific aspects of the Raspberry Shake they host and data they collect. During the August 14th 2021 earthquake, the group was used to share information about damage and rumors.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Yet, this communication strategy is still incomplete and requires improvements. For instance, volunteers requested pedagogical support to better play their ambassador role among their community. Communication towards the general public also needs to gain visibility and accessibility. As part of an iterative process, additional interviews and assessment will help us improve the communication strategy. We will also include additional partners (such as schools, disaster management institutions, etc.) and test other methods such as a Virtual Reality tool.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;We argue not only that assessing the public needs is essential to build an inclusive and efficient communication strategy but also that the citizen-science approach is a strong asset to achieve this goal.&lt;/p&gt;&lt;p&gt;&lt;br&gt;&lt;br&gt;&lt;/p&gt;

The analysis of the seismicity catalog (1996 to 2019) covering the region from the Jura mountains to Corsica provides a first-order image of the distribution of earthquakes, highlighting large structures such as the Briançonnais and Piedmontais seismic arcs, the eastward deepening of the focal depths through the Western Alps, several large active faults (e.g. Belledonne, Middle Durance, Ligure). Over this period the magnitudes are moderate and the focal mechanisms of the main events display a diversity of seismic behaviors that can be explained by the complexity of the different geological domains with a more or less strong structural inheritage, by variable rheological characteristics at the scale of the crust and by the joint action of different mechanisms of deformation. The distribution of the historical events is in fairly good agreement with the instrumental seismicity, but several earthquakes of M>6 are highlighted since the 14th century until the beginning of the 20th.

The Ubaye Region is the most seismically active region in the Western Alps, with earthquakes that were commonly felt by the population and that even damaged local villages and cities. Since the first testimonies in 1844, this area has been regularly struck by seismic swarms with a high number of events, such as in 2003–2004 or 2012–2015, or by mainshock–aftershock sequences with a magnitude up to ML 5.3 in 1959. In this paper, we analysed both historical records and instrumental seismicity in the light of geological observations. Some earthquakes could be associated with known faults, even if most of them occurred on blind, unknown faults that reveal a highly fractured basement. The abnormal level of seismicity, together with its peculiar behaviour, suggests complex driving processes involving not only tectonic loading but also fluid pressure.

The Ubaye Region, where the city of Barcelonnette is settled, is the most seismically active region in the French Western Alps since at least two centuries. Seismicity in this area exhibits a dual behaviour, with mainshock-aftershock sequences alternating with abnormally high rate of seismicity associated with seismic swarms. Understanding processes triggering such a peculiar seismic behaviour is of primary importance in order to assess the seismic hazard in this region. The latest swarm activity started on February 26, 2012, with an earthquake of moment magnitude 4.2. It was followed two years later (on April 7, 2014) by a shock of magnitude Mw 4.8. From the first earthquake to the end of 2016, the seismic level has not returned to the background level and shares the same characteristics as a seismic swarm. With the aim to discuss the seismogenic processes involved in the area, we focused on the two months following the 2014 mainshock (Mw=4.8). During this period, a dense temporary network (7 stations) was operating at a maximal distance of 10km from the epicentre area. We analysed this period starting with a double-difference relocation of ~ 6,000 earthquakes previously detected by template-matching. These hypocentres did not align on the fault plane of the 2014 mainshock, but on conjugated structures belonging to the 2-km wide damaged zone of the main fault plane and on remote structures with various orientations further away. We then computed 99 focal mechanisms from a joint inversion of P polarity and S/P ratio to clarify the geometry of the active structures. Many nodal planes are inconsistent with the structures deduced from the alignments of the earthquake locations. The stress-state orientation obtained from those focal mechanisms (σ1 trending N27°± 5°, plunging 50°± 9°, a σ2 trending N215°± 5°, plunging 40°± 9°, and a sub-horizontal σ3 trending N122°± 3°) is consistent with those previously calculated in the area (Fojtíková and Vavryčuk, 2018). Nevertheless, some structures are unfavourably oriented to slip within this stress-field, suggesting that additional processes are required to explain them. As the presence of fluids was highlighted for the 2003-2004 and the 2012-2015 crisis, we calculated the fluid pressure needed to trigger slip on the planes from the focal mechanisms using Cauchy's equation. We found that a median fluid-overpressure of ~20 MPa (range between 0 to 50 MPa) is needed to cause slip. Although the origin of fluids and how they are pressurized at depth remains open. The fluid processes seem to be the most favourable additional processes and were also proposed to explain the 2003-2004 crisis.