Recent studies showed that seemingly random Slow Slip Events (SSEs) can display chaotic patterns within the largest source of seismic hazards in New Zealand, the Hikurangi subduction zone. Some irregular SSE occurrences are therefore not arbitrary but behave with short-term predictability. However, the forecasting challenge persists as observations remain too short and noisy to constrain purely data-driven solutions, calling for a physics-based modelling approach. Here we propose a physical model of two coupled oscillators, each capturing the behaviour of a single slow-slip patch, for the deep Kaimanawa and the shallow East Coast SSEs respectively. The simplified model successfully reproduces the type of chaotic behaviour observed at the Global Navigational Satellite System station in Gisborne, yielding SSEs of appropriately varying amplitude and duration. Those results reveal that the multi-physics response of the shear zone strongly controls the underlying system, even before accounting for any geometrical complexity or distribution of material properties.

The Alps are a dynamic orogen, as evidenced by recent crustal uplift and seismic activity. Earthquakes are primarily occurring along the many pre-existing Neogene faults formed during the Alpine orogeny, making it challenging to predict which faults are being reactivated. Limited geophysical data, low strain rates, high erosion rates, and widespread faulting complicate the detection of active faults in low-strain regions. Currently there is a lack of knowledge about the abundance, architecture, and properties of active faults in the Alps, which is however critical for evaluating the regional seismic hazard. This study adopts an interdisciplinary approach to identify and characterize active faults in the Rawil depression and surrounding areas north of the Rhône-Simplon fault system, located in the southwestern Swiss Alps. A comprehensive seismotectonic description of the region is achieved by combining information from recent high-precision earthquake catalogs derived from relative relocations covering about 40 years, new fault maps using remote sensing and field surveys, updated stress inversion from extended focal mechanism catalogs and paleostress inversion from fault slip data, as well as GNSS data. Results from 3D imaging of active faults at depth, based on the high-precision hypocenter catalogs, reveal that subvertical faults, striking E-W, host most of the present-day earthquakes in the region. This imaging also uncovers previously unknown NW-SE striking active faults potentially contributing to the overall strain distribution in this part of the Alps. Compared to principal stress orientations in the upper crust derived from focal mechanisms, faults striking in both E-W and NW-SE directions appear to be optimally oriented for reactivation in the current stress field. Recent crustal stresses, consistent with the results obtained from paleostress inversion indicating NE/SW-directed transtension, suggest a relatively constant stress regime over the last couple of million years. This implies similarities between exhumed and seismically active faults at depth. The agreement between fault geometries exhumed at the surface and reconstructions of active faults at depth, as determined by hypocenter-based 3D imaging of active faults, support these findings. In conclusion, our study demonstrates that such interdisciplinary studies provide valuable insights into the deformation processes in tectonically active regions, contributing to refined seismic hazard assessments.

Meteoric water may or may not infiltrate deeply into high-relief mountain ranges. Along its subsurface circulation path, the water heats up according to the background geothermal gradient and eventually emerges at lower elevation as thermal springs. Whether such topographically-driven circulation establishes or not depends on the host rock’s permeability and/or the hydraulic head. In terms of permeability, fault zones play an important role as they can provide preferential flow paths for fluids. This is particularly the case of active fault zones along which recurring slip counteracts clogging caused by mineral precipitation often found along non-active structures. Thus, the investigation of 4D fault and fracture geometries and their kinematics is a means to understand the locations and dynamics of geothermal systems in orogenic belts. Here, we present preliminary results from the ongoing GeoTex research project, which aims at better defining the geothermal potential of the Rhône Valley, an area of rugged topography in SW Switzerland. The Rhône Valley represents a geothermally active zone within the Alpine orogen, which is characterised by numerous thermal springs, regional-scale faults and enhanced seismic activity. It is therefore a promising setting to explore further for exploitation. Based on structural data from fieldwork and quantitative remote sensing, we characterise fault geometries (i.e., spatial orientation, relationship of intersecting fault families as well as kinematics) in the vicinity of known thermal springs. Observable paleo-fluid pathways marked by veins and rock alteration are being considered as analogues for recent thermal water circulation. These circulation paths are linked to major Alpine structures in the underlying basement units, such as large-scale strike-slip faults or the axial planes of uplifting basement domes. Our results suggest spatial correlations between the locations of hydrothermal springs and the 3D structure of the host massifs. Specifically, basement–cover contacts exert geometric and lithologic control at some sites, whereas locally dilatant domains along strike-slip faults as well as intersections of fault families focus outflow at other sites. Through the above approach in combination with seismological data, we have derived conceptual models for fluid flow, which may help to predict the locations of blind active geothermal systems elsewhere in the Rhône Valley.

Worldwide, fault zones in carbonates regularly host medium to large earthquakes including recent ones in the Mediterranean and Middle East. In addition to that, faults can control fluid flow by either acting as a conduit or seal for fluid pathways and should be considered in e.g., geothermal exploration. Hence, understanding the (micro-) structural evolution of these fault zones as well as fluid mediated geochemical processes involved in their dynamic deformation history allows to better address topics of societal and economic relevance ranging from seismic hazards to the exploitation of natural resources. Unfortunately, active in-situ deformation at depth is difficult to access, emphasising the need for investigations on suitable exhumed analogues.This study focuses on the microstructural and geochemical record of a recently exposed seismogenic dextral strike-slip fault zone in the seismically active southwestern Swiss Alps. Due to excellent outcrop conditions on glacially polished rock surfaces and a wide range of preserved tectonites and associated deformation structures, this particular fault zone provides a valuable record of potential paleoseismicity in carbonates. We combined microstructural analyses with micro-chemical and isotope data in order to reconstruct the spatio-temporal evolution of high-strain domains at variable crustal levels throughout exhumation. While the microstructural record allows us to differentiate between rate-dependent brittle and viscous deformation phases, we use the geochemical fingerprint to distinguish and characterize individual fluid pulses.Here, we present microstructural evidence of fast, possibly seismic, deformation along a principal slip zone. While injection structures containing fluidized material, suggest highest deformation rates as feasible for seismic events, repeated brittle deformation that was accompanied by the formation of cataclasites and calcite veins, hints towards fast seismic to sub-seismic rates.We also found that newly formed calcite crystals, in veins and linkage zones, show significantly decreasing δ18OSMOWvalues, as low as 5 ‰ δ18OSMOW, implying an influence of meteoric water. Clumped isotope thermometry of such calcites resulted in temperatures of 65-95°C, which are approximately 100°C lower than Tmax in the area. This suggests that the analyzed material did not record any potential shear heating. Moreover, the investigated tectonites have most likely formed along a retrograde exhumation path. In combination with detailed observations on the m- to 10er-m-scale our observations provide a dataset that allows direct comparison of different deformation processes and correlation of paleo-seismicity to fluid flow in fault zones. Further, we contribute to the longstanding discussion of differentiating microstructural evidence for seismic slip from slow or aseismic slip in carbonate hosted fault zones.

The base data for any seismotectonic study consist of accurate and precise hypocenter information, consistent magnitude estimates, and focal mechanisms derived either from the analysis of first-motion (FM) polarities or moment-tensor (MT) inversions. In this study, we present a new baseline seismotectonic earthquake catalog of Switzerland and surrounding regions (SECOS24), which covers the Central Alps (CA) region between 45.4°N/5.6°E and 48.4°N/11.1°E. The SECOS24 catalog includes instrumental seismicity routinely detected and located by the Swiss Seismological Service (SED) between 1975 and 2024 (about 49 years). For the digital era of the SED bulletin (phase picks and seismograms available in digital form) starting in 1984, hypocenters were consistently relocated in absolute terms using a recent Pg and Sg 3-D velocity model. Starting from these improved hypocenters, double-difference relative relocations were performed at different scales (single clusters as well as at regional scales), combining differential times from manual picks and waveform cross correlations. Based on available solutions and resulting location quality, a preferred solution was selected for each hypocenter of the SECOS24 catalog, in order to provide the maximum possible hypocenter accuracy and precision for each event. The SECOS24 catalog contains about 36,000 earthquakes with magnitudes ranging between ML -0.7 to 5.3. In addition to ML, the catalog reports complementary magnitudes for a subset of events. For 71 events, an MW magnitude was derived from a revised MT inversion for events starting in 1999. For events since 2009, a spectral MW was calculated if possible. This magnitude compilation allows for the assessment and improvement of existing ML-MW scaling relations. Finally, we linked each hypocenter with the revised MT catalog as well as solutions of an augmented FM catalog, which contains 492 high-quality, manually reviewed mechanisms based on P-wave first-motion polarities. The SECOS24 catalog is used for down-stream seismotectonic analysis of the CA region. In this presentation, we show updated maps of seismicity and moment release in the CA and their foreland. In addition, we provide updated maps of deformation regimes and stress orientations derived from the analysis and inversion of the FM data. Besides previously known features, the SECOS24 catalog reveals several new features in the CA and their foreland like newly imaged seismogenic fault zones, lateral changes in the deformation regime along the Alpine Front of the CA, and ongoing shortening at shallow crustal levels in the Jura fold-and-thrust belt. In addition, the updated stress inversion provides more stable results and, in several places, higher spatial resolution in comparison to previous studies. The SECOS24 catalog therefore contributes to an improved understanding of present-day tectonic processes in the CA region and is crucial input for next-generation seismic hazard models of the region.

Pre-existing geological discontinuities such as faults and fractures represent structural and mechanical discontinuities in rocks which influence earthquake processes. As earthquakes occur in the subsurface, seismogenic reactivation of pre-existing fracture networks is difficult to investigate in natural settings. However, it is well-known that there exists a physical link between both fractures and earthquakes since an earthquake's magnitude is related to the ruptured fracture area and therefore fracture length. Furthermore, fractures and earthquakes exhibit similar statistical properties, as their size distributions follow power laws. In this study, we exploit the relation between the size (or length) distributions of pre-existing fractures and earthquakes to decipher the seismic deformation processes within the exhumation-related orogen-internal setting of the southwestern Swiss Alps, which due to its well-monitored seismic activity and the excellent outcrop conditions provides an ideal study site. Characterizing exhumed fracture networks from different tectonic units based on multi-scale drone-based mapping, we find that power law exponents of 3D fracture size distributions generally range between 3 and 3.6. Comparing these values with the depth-dependent exponents of estimated earthquake rupture lengths, we observe significantly larger values of 5 to 8 for earthquake ruptures at shallow depths (< 3 km below sea level (b.s.l.)). At intermediate crustal depths (∼ 3 to 9 km b.s.l.), the power law exponents of fractures and earthquakes appear to be similar. These findings imply depth-dependent differences in the seismogenic reactivation of pre-existing fractures in the study region: while partial rupturing is the prevailing deformation mechanism at shallow depths, fractures are more likely to rupture along their entire length at intermediate crustal depths. Therefore, the present-day near-surface differential stresses are likely insufficient to rupture entire pre-existing fractures seismogenically. Our findings have direct implications for seismic hazard considerations, as earthquakes that rupture along entire fractures appear to become less likely with decreasing depth.

AbstractCurrent earthquake forecasting approaches are mainly based on probabilistic assumptions, as earthquakes seem to occur randomly. Such apparent randomness can however be caused by deterministic chaos, rendering deterministic short‐term forecasts possible. Due to the short historical and instrumental record of earthquakes, chaos detection has proven challenging, but more frequently occurring slow slip events (SSE) are promising candidates to probe for determinism. Here, we characterize the SSE signatures obtained from GNSS position time series in the Hikurangi Subduction Zone (New Zealand) to investigate whether the seemingly random SSE occurrence is governed by chaotic determinism. We find evidence for deterministic chaos for stations recording shallow SSEs, suggesting that short‐term deterministic forecasting of SSEs, similar to weather forecasts, might indeed be possible over timescales of a few weeks. We anticipate that our findings could open the door for next‐generation SSE forecasting, adding new tools to existing probabilistic approaches.

Understanding orogen-internal seismic deformation in regions with diffuse spatial earthquake occurrence is challenging. To gain deeper insights into the processes driving seismic fault reactivation, it is crucial to obtain information on the ubiquitous pre-existing fracture patterns. In orogens with long tectonic histories – such as the Alps – such patterns can be complex, and information on their appearance is mainly limited to observations of faults at the surface, while the detailed patterns at depth remain mostly unknown. Moreover, the link between such surface-based fault observations and active seismicity is often ambiguous. However, it has been shown that both earthquake magnitudes (Gutenberg-Richter law) and various fault properties (e.g., length, displacement) follow power-law distributions.In this work, we aim to investigate the potential relationship between the scaling properties of faults and earthquakes, which has been little explored. To this end, we use statistical tools based on field data collected with remote sensing techniques at different scales to quantitatively characterize the length distributions of exposed fault networks at different study sites in the southwestern Swiss Alps. Due to the good outcrop conditions at high elevations, the dense seismic monitoring network, and the enhanced earthquake activity, this region provides an ideal natural laboratory for the study of orogen-internal seismicity. By combining fault trace maps from three different scales, we are able to derive power law parameters and decipher similarities in scaling exponents for the different sites studied. Assuming that the fault networks exist in a similar form at depth and form the pre-existing discontinuities along which recent earthquakes develop, we compare the derived scaling laws with the frequency-magnitude distribution of local seismicity over the past 15 years. Here we find similar scaling properties between the seismicity and fracture networks only at depths below 3 km. However, in shallower regions, the large discrepancy between the scaling laws suggests that partial seismic ruptures of individual fault segments are more common than at greater depths. Such a statistical comparison of fault and earthquake scaling laws provides interesting insights into orogen-internal seismic deformation and fault reactivation processes that also have implications for regional seismic hazard.

Understanding how bedrock properties influence the valley‐forming processes of Alpine landscapes is an outstanding challenge. A multi‐methodological approach was used to uniformly quantify fault frequency, orientation, and rock hardness of crystalline basement rocks to evaluate their impact on the erosional processes that shaped the valley of the Aletsch Glacier, Switzerland. We show how variations in fault frequency and orientations, imposed by the inherited collisional framework of the area, controls the local erodibility of the valley, affecting both hillslopes and channel erosion processes. Our results highlight how tectonic preconditioning exerts a first‐order control on the efficiency of erosion in the mountain chain, elucidating an integral link between deep‐seated collisional dynamics and surface‐based mountain shaping. Moreover, our results express the importance of a uniform, quantitative characterization of bedrock properties to comprehend the interaction and variability of erosional processes and hazards distributed within the valley systems.

Despite the fact that earthquake occurrence can be strongly influenced by the architecture of pre‐existing faults, it remains challenging to obtain information about the detailed subsurface geometries of active fault systems. Current geophysical methods for studying such systems often fail to resolve geometrical complexities at sufficiently high spatial resolutions. In this work, we present a novel method for imaging the detailed 3D architectures of seismically active faults based on high‐precision hypocenter catalogs, using nearest neighbor learning and principal component analysis. The proposed approach enables to assess variations in fault instabilities and kinematics. We apply the method to the relatively relocated St. Léonard (max. M L = 3.2) and Anzère (max. M L = 3.3) microearthquake sequences in the Southwestern Swiss Alps, revealing strike‐slip fault systems with interconnecting stepovers at depths of 3–7 km and lengths ranging from 0.5 to 2 km. In combination with additional information about fault instabilities and kinematics, we observe significantly reduced earthquake migration velocities and fault locking processes within the stepovers. Understanding such processes and their role in the propagation of strain across stepovers is of great relevance, as these structures can potentially limit earthquake ruptures but also represent possible locations for the nucleation of larger ruptures. Our proposed method is expected to be broadly useful for further applications such as monitoring hydraulic fracture stimulations or geothermal exploration of natural, fluid‐bearing faults. Conducting similar high‐resolution spatiotemporal analyses of microseismic sequences has the potential to greatly enhance our comprehension of how the 3D fault architecture impacts seismogenic fault reactivation.

&lt;p&gt;The susceptibility of catchment rocks to glacial erosion may control the evolution of valley morphology in high-relief mountain ranges such as the Alps. Non-uniform proneness to bedrock erosion may indeed localize knickpoints and overdeepenings characteristic of glacial valleys. Yet, little is known about the explicit influence of bedrock properties (i.e. lithology, hardness, and geological structures) on glacial erosion processes. In this study, we select the Great Aletsch Glacier (Swiss Alps) as a natural laboratory to document and investigate the relationship between bedrock properties and subglacial erosion mechanisms. The Great Aletsch Glacier with a length of more than 20km and an ice thickness of up to 800m is the largest glacier in Central Europe. The underlying bedrock consists of the crystalline basement units of the Aar massif (gneiss, granite, and granodiorite) and is dissected by a large number of steep faults and former ductile shear zones. Geological and remote sensing lineament mapping combined with 3D geological modelling allowed us to make a large-scale characterization of the lithologies and structures&amp;#8217; spatial frequency over the entire length of the glacier. Additionally, we performed field-based rock hardness analyses (Schmidt hammer) along the glacier&amp;#8217;s bedrocks (intact rock and faulted/sheared domains) to testify for structure-controlled erosion behaviour. Obtained results demonstrate that: (i) the typology and distribution of faults and shear zones are not uniform over the entire length of the glacier; (ii) high-frequency structure domains correlate with overdeepenings and/or abrupt glacier flow deflection in the direction of the strike of the structures; (iii) low-frequency structure domains correlate to the absence of overdeepenings and a straight glacier trajectory. In terms of erosive resistance domains of intact rock masses show high hardness values for each of the investigated lithologies without substantial variability between the different basement rocks (rebound values ranging from 45 to 60 N/mm&lt;sup&gt;2&lt;/sup&gt;). On the contrary, faulted or sheared domains show a significant drop in hardness value (rebound values ranging from 10 to 40 N/mm&lt;sup&gt;2&lt;/sup&gt;). Based on these results we propose that, for the case of the Great Aletsch Glacier, differences in crystalline basement lithologies do not exert an important role in glacial erosion. We postulate instead that the non-uniform spatial distribution of geological structures imposes a major control on the development of the glacial valley. The substantially reduced bulk hardness within high-frequency structure domains renders indeed the bedrock to be more prone to efficient glacial erosion process at these sites (i.e. glacial quarrying) and therefore to the development of large-scale overdeepenings, local scouring, or changes in the glacier flow direction. By contrast, the more massive undeformed and therefore less erosive low-frequency structures domains coincide with sections with no knickpoints or overdeepenings. In times of global warming and glacial retreat, such structure-controlled bedrock incisions are prone for further enhanced surface weathering and gravitation-controlled erosion processes, such as rockfalls and landslides, providing sites of enhances natural hazard potential.&lt;/p&gt;

Despite the generally accepted concept that most earthquakes occur along pre-existing faults, the complex 3D geometries of seismically active fault systems at depth often remain unresolved. However, earthquake nucleation and migration processes are heavily influenced by the geometries and properties of such pre-existing structures, which limits our general understanding of earthquake nucleation and fault interactions.Under the assumption that faults are reactivated at spatially and temporally different localities, previous studies have attempted to derive fault geometries from hypocenter locations, but were usually limited by the precision of relocation techniques. Enabled by the recent advances in hypocenter relocation techniques, we present a novel Monte Carlo-based method that uses relatively relocated hypocenters and their uncertainties to image geometries, stress states and kinematics of seismically active fault systems. The application of the developed Python toolbox on a natural earthquake sequence along the Rhone-Simplon fault zone in the northern Valais (Swiss Alps) reveals active strike-slip faults with a contractional stepover. Performed stress analyses indicate varying stress states along the fault system, which has direct implications for fault properties such as the reactivation potential or the fluid transmissivity. Overall, we document the migration of an earthquake swarm across a complex strike-slip fault system at an unprecedented spatiotemporal resolution.Our toolbox can be applied to high-precision hypocenter catalogs of natural earthquake sequences or hydraulic stimulation experiments, which could help to improve our understanding of the role of pre-existing faults on earthquake nucleation and migration processes at various scales.

Owing to still ongoing convergence within the Europe-Adria collision zone, Switzerland is affected by heterogeneously distributed moderate seismic activity. The project SeismoTeCH aims to improve the understanding of the links between the seismic activity, existing fault structures and geodynamics in Switzerland and its close vicinity. We started with compiling existing databases on faults (fault densities, lengths and orientations), seismic activity (spatial hypocenter and magnitude distributions, detection of seismic lineaments, focal mechanisms), orientations of mean principal stress axes and recent crustal movements (GNSS, high precision levelling) in order to establish potential correspondences as well as regional variations. Due to the long-lasting Alpine deformation, fault-orientation patterns as well as fault-densities vary between specific tectonic domains (Jura/North-Alpine foreland, Alpine frontal sediment nappe systems, External Crystalline Massifs, inner-Alpine domains and Southern Alps). Despite this variability, the fault patterns show first order correlations with the spatial arrangement of newly mapped seismic lineaments, earthquake focal planes and associated focal mechanisms. This correlation indicates a regional geodynamics-controlled reactivation of the specific fault networks during current crustal movements. In terms of recent surface movements, variations in (i) horizontal GNSS movements with respect to stable Europe and (ii) vertical uplift (from levelling and GNSS data) have to be discriminated. (i) From E to W in southern Switzerland (S-Grisons–Ticino–Valais, S of Rhone-Simplon line), horizontal movements change from NW to SW directions (velocities >0.5-0.8mm/yr). The southern Adria crustal block shows minimal to no lateral motions in the W-part and a clear NE-directed motion that is progressively increasing towards the E. This motion can be correlated with the so-called counter-clockwise rotation of the Adriatic plate. North of aforementioned domain, N- to NW-directed movements dominate but velocities decrease progressively from the central Alpine domains (<0.3-0.5mm/yr) towards southern Germany, where they are generally small (<0.3-0.4mm NE-CH). This variability between southern and central/northern Switzerland as well as that from E to W, respectively, is accommodated by NE-SW (Rhone-Simplon system) and N-S oriented strike-slip systems. (ii) Most substantial vertical uplift occurs in a WSW-ENE oriented central Alpine belt ranging from the Valais to the Grisons. Note that absolute values of this vertical uplift are 2-3 times larger compared to horizontal movements in the corresponding domains. Focal mechanisms in this high uplift belt indicate orogen-parallel NE-SW extension mainly in the S-Valais and Grisons accommodated by active normal faulting S of the Penninic front. Uplift rates gradually decrease towards the N- and S-Alpine foreland as well as towards Austria and France. Data even suggest tendencies of subsidence at very low rates in the Bresse graben, Upper Rhine graben as well as somewhat more pronounced ones in the eastern Po-plane but not in the CH-Molasse basin. Parts of the northern Alpine foreland exhibit upper to lower crustal seismic activity, while in the thick-crustal-root-enhanced high uplift domains upper crustal seismicity dominates and earthquakes below 20km depth do not occur. Overall recent surface movements and seismicity in and along Central Alpine crustal blocks are affected by buoyancy-driven vertical combined with transpressional/-tensional horizontal movements indicating a lithosphere-scale geodynamic forcing.

The retreat of the Great Aletsch Glacier is accompanied by a series of slope failures in solid bedrock, which are heavily influenced by the presence of pre-existing deformation structures. Since the 1880's, the Great Aletsch Glacier has shortened by more than 3 km and decreased about 400 m in thickness. As a reaction to the loss of the stabilizing effect of the ice, one of the largest active deep-seated landslides in the European Alps with an affected surface area of about 1.5 km(2), called Moosfluh landslide, is evolving. In this study, a multimethod approach combining fieldwork, remote sensing techniques and microseismic monitoring is used to assess the effect of preexisting structures on the landslide deformation processes. The landslide evolution from 2008 to 2018 could be reconstructedwith high spatial resolution. Surface deformation analysis reveals the concentration of high deformation in narrow zones, allowing to directly link pre-existing tectonic and exhumation structures with landslide deformation processes. Toppling as the main gravity-driven process is enabled by reactivation of NE-SW striking, steeply SE dipping Alpine Handegg phase shear zones. Differences in the lateral detachment processes are attributed to shear zone bridges in the NE as well as fractures and shear zones similarly oriented to Alpine Oberaarb phase shear zones in the SW. At the landslide toe, a transition fromtoppling to slidingmechanism due to the formation of a continuous basal detachment surface can be observed, which is favored by the presence of exfoliation joints. The dramatic acceleration of theMoosfluh landslide in autumn 2016 is directly related to an increase in glacier height loss rate, which implies that glacier retreat is themain trigger of the landslide. A temporal stabilization of the landslide is recorded after 2017, most probably caused by the self-stabilizing properties of flexural toppling. However, microseismic data records a lateral propagation of the landslide, following the retreating Great Aletsch Glacier. (C) 2021 Elsevier B.V. All rights reserved.

The Rawil depression north of the Rhone Simplon fault zone (southwestern Swiss Alps) was host of the Mw = 5.8 Sion earthquake in 1946 (Fäh et al., 2011). It is nowadays one of the seismically most active regions in Switzerland and seismicity forms a cluster, which is elongated approximately in WSW-ENE direction over 40-50 km. In November 2019, a remarkable earthquake sequence occurred within the center of this cluster north of the village of Anzère, with more than 300 earthquakes up to ML = 3.3 recorded by the Swiss Seismological Service within 20 days. Detecting associated full-scale 3D fault patterns solely based on earthquake hypocenters is challenging because of commonly too limited spatial resolution and insufficient number of seismic events. Within the framework of SeismoTeCH, we aim to improve these limitations by a combination of high-precision hypocenter relocation techniques, reconstruction of subsurface fault patterns and correlative links between surface and subsurface data. Assuming that a fault is seismically active multiple times and that the seismic stress-release is initiated at different locations along the fault, we can calculate 3D fault plane orientations from the hypocenter locations. Together with the 17 focal mechanisms derived for the Anzère sequence, we are able to gain geometrical and kinematic information of the seismic faults in 3D. Our analysis reveals a seismically active transpressional step-over structure within a dextral strike-slip fault zone. With remote sensing and field observations, we detect exhumed faults with similar orientations and kinematics that presumably represent step-over structures, interconnecting previously known strike-slip fault zones. Although seismic activity occurs at depths between 3-5 km, we conclude that the observed surface fault systems in the Rawil depression can be correlated in terms of fault patterns with those assumed at depth. The linkage of the recent seismicity with structural observations of exhumed, potentially paleo-seismic faults in combination with recent hypocenter relocation techniques therefore have great potential to provide further insights into fault linkage and earthquake rupturing processes. References Fäh, D., Giardini, D., Kästli, P., Deichmann, N., Gisler, M., Schwarz-Zanetti, G., Alvarez-Rubio, S., Sellami, S., Edwards, B., Allmann, B., Bethmann, F., Wössner, J., Gassner-Stamm, G., Fritsche, S., Eberhard, D., 2011. ECOS-09 Earthquake Catalogue of Switzerland Release 2011. Report and Database. Public catalogue, 17.4.2011. Swiss Seismological Service ETH Zürich, Report SED/RISK/R/001/20110417.