This project is based on the seismo@school program, which was initiated by the University of Lausanne and the HES-SO Valais-Wallis in recent years and in which 22 schools in the cantons of Valais and Vaud have so far participated. Thanks to a two-year AGORA project funded by the SNSF entitled "Promoting earthquake awareness in Switzerland", we will extend this program to the whole of Switzerland.

In this project, in collaboration with the STEM Center at ETH Zurich, we will develop teaching materials and activities for secondary schools (ages 12-18) that will allow students to explore earthquake-related topics from current research. We will also provide schools with simple seismic sensors that allow students to record and analyze earthquake seismograms at their school. With our Switzerland-wide, multilingual seismo@school program, we want to contribute to education about earthquakes, earthquake hazards and risks in Switzerland and worldwide, strengthen STEM subjects in schools, as well as promote national and international school partnerships.

Despite intensive research, scientists cannot predict exactly when and where the next major earthquake will occur. The ERC Synergy project "FEAR" aims at a better understanding of the physics of earthquake processes. To this aims, researchers will generate small earthquakes under controlled conditions at a depth of more than one kilometre and on a scale of ten to one hundred metres. They will measure a variety of earthquake parameters using a dense sensor network and then analyse them. The consortium hopes to gain a better understanding of the dynamics of earthquakes. The new findings will also be used to advance experiments on the safe use of geo-energy and to improve the predictability of earthquakes. The experiments will take at the "Bedretto Lab", a rock laboratory in the Swiss Alps, built by ETH Zurich and the Werner Siemens Foundation. It offers FEAR a unique research environment.

CORE is an EU project funded by the European Commission under Horizon2020 research and innovation programme and involves 19 partners in Europe. Its main objective is to make societies better prepared to face and overcome natural and human-made disasters. Through a transdisciplinary approach, scientists from different fields and various stakeholders from society are involved. The project will seek to put the citizens at the core of disaster resilience and preparedness, supporting communities to enhance their preparedness and rapid recovery.

Defining at best the expected scenarios and the difficulties of individuals and socio-economic structures is essential to make recoveries more effective and efficient. Recommendations and guidelines from CORE will foster a culture of improved preparedness, adaptability, and resilience to risks. In addition, particular attention will be paid to the most vulnerable groups during such disasters: the disabled, the elderly, people with economic difficulties, women, or children. Great attention will also be paid to education in schools, training activities and communication through social media.

SMILE is a Marie Sklodowska-Curie doctoral network supported by the European Union's Horizon Europe framework program with the objective to train a new generation of young researchers for the successful deployment of subsurface low-carbon energy sources. The deployment of geothermal energy, and subsurface storage of energy and CO₂ can help fight climate changes and limit the temperature increase as laid out in the Paris Agreement. However, some early geo-energy projects have occasionally developed unpredicted consequences, such as felt and damaging induced earthquakes, dampening public perception on geo-energies. The various processes involved in geo-resources exploitation (e.g., hydraulic, geomechanical, geochemical and thermal effects) imply complex interactions that cannot be predicted without considering the dominant coupled processes. SMILE seeks to overcome these obstacles in the development of geo-energy solutions by comprehending and forecasting linked processes. The trained researchers will have the ability to suggest creative ways to ensure that subterranean low-carbon energy sources are successfully deployed while safeguarding related ecosystems and groundwater. Doctoral candidates undergo interdisciplinary training in experimental, mathematical, and numerical modeling of coupled processes, upscaling techniques, and ground deformation monitoring using field data from pilot tests and industrial sites, enhancing their applicability in academia, industry, and public sector.

SED's participation in SMILE aims to develop an experimental study on the interaction between reactive pore fluids and rock matrix in caprocks and reservoir rocks. Data are collected at lab scale (e.g. the Rock Physics and Mechanics Lab, ETH Zurich) and in situ at pilot projects (e.g. Mont Terri, Bedretto Underground lab, as well as at Icelandic CO₂ storage facilities), aiming to link mechanical/hydraulic parameters and fluid-rock interaction. The goal is to create a comprehensive dataset on geomechanical parameters related to fluid-rock interaction in caprock/reservoir rocks, which will be used in numerical simulations.

The Swiss Energy Strategy foresees CO₂ capture and underground storage, possibly abroad, among the necessary measures to reach the net zero target by 2050. DemoUpCARMA, the partner project of DemoUpStorage, explores as one pathway to negative emissions the transport and storage of Swiss biogenic CO₂ in Islandic basalt as well as this pathway’s potential for upscaling. Since a safe and permanent storage of the Swiss CO₂ is an indispensable requirement, DemoUpStorage takes the lead in closely monitoring the injection and the dispersion of the Swiss CO₂ in the Islandic underground at a site that has high potential for upscaling. For the injection, a novel technique is used, where the CO₂ is dissolved in sea water instead of fresh water. The findings of DemoUpStorage will further advance the Swiss Roadmap for geological CO₂ storage through knowledge acquisition and transfer, as well as capacity building.

DemoUpStorage has the following objectives:

• To independently evaluate if injecting CO₂ dissolved in seawater into basalts near the coast in Iceland is a safe, permanent, cost-effective, and environmentally acceptable pathway for CO₂. Together with DemoUpCARMA, DemoUpStorage will further evaluate if this approach has the potential to be upscaled and it would allow to store up thousands tons/year of Swiss CO₂ from 2024 onwards of Swiss CO₂ from 2024 onwards.
• To advance and benchmark borehole- and surface-based monitoring techniques and computational modelling tools to reliably track and forecast the migration of CO₂ in different geological settings, including those relevant for future CO₂ injection tests in Switzerland.
• To build up within Switzerland an interdisciplinary competence in monitoring and modelling CO₂-injection with the ultimate goal of being ready for future projects in Switzerland.

Phase 1 (2023-2027). Understanding earthquake risk at the national and sub-national levels is essential for developing effective policies and measures to mitigate this risk. The Earthquake Risk Model of Switzerland (ERM-CH23), developed between 2027 and 2022, and released in early 2023, is the culmination of a multidisciplinary effort to provide, for the first time, a comprehensive assessment of the potential consequences of earthquakes on the Swiss building stock and population. Developed as a national model, ERM-CH23 relies on very high-resolution site amplification and building exposure datasets, which distinguishes it from most regional models to date. Multiple loss types are evaluated, ranging from structural/nonstructural and contents economic losses, to human losses, such as fatalities, injuries and displaced population.

Phase 2 (2023-2027). ERM-CH23 includes a variety of products designed to meet the needs of a very diverse audience. Earthquake scenarios quantify the losses caused by individual events and are typically used by cantonal authorities in preparedness exercises and help raise awareness of seismic risk among the general public. Rapid impact assessments, conducted in the immediate aftermath of an earthquake, help manage the consequences of a damaging earthquake. In the hours and days following an earthquake, they are the foundation upon which the Blue Light organizations rely in their response efforts. Probabilistic seismic risk calculations for individual building portfolios assess the financial exposure of entities responsible for insuring property owners in Switzerland.    

In the second project phase, the model undergoes further improvements, such as the introduction of daytime-dependent loss calculations and updates to administrative community layers. Model maintenance and data curation, ensuring compatibility with the ever-evolving OpenQuake software, and finally calculating different products to meet the needs of different stakeholders are important aspects of this phase. Additionally, outreach efforts and the development of learning modules are important activities to enhance understanding and preparedness.

As a local, versatile, clean, and renewable energy source, geothermal energy can contribute to achieving Switzerland’s energy and climate objectives. Worldwide, numerous geothermal projects have been successfully operating for decades. Unfortunately, some have also been aborted during the reservoir construction or operation phase. Today, adequate risk governance of induced seismicity is perceived as essential for establishing safe and economically viable geothermal projects.

In Switzerland, the subsurface is under the sovereignty of the cantons. Therefore, the cantonal authorities in charge of the permitting, concessioning, and regulatory oversight must have access to independent, state-of-the-art seismological expertise. Furthermore, independent seismic monitoring and competent project oversight are important contributions to risk governance and can build and maintain public acceptance of geothermal projects.

GEOBEST2020+ ensures that the Swiss Seismological Service (SED), the federal agency for earthquakes, can provide seismological expertise and baseline seismic monitoring services to the cantons at no cost and independently of the operators of geothermal projects:

Seismological consulting:

SED experts can support the cantonal authorities with:

• defining induced-seismicity-related content requirements for all relevant cantonal authorizations mandatory for geothermal projects,
• reviewing seismological aspects of permit and concession requests submitted by the project operators,
• providing independent, canton-specific information on geothermal energy and seismicity to the public.

Seismic monitoring and earthquake alarming:

SED can provide the baseline seismic monitoring, including:

• installation of a customized seismological monitoring network,
• automatic real-time earthquake analysis, rapidly reviewed by experienced seismologists,
• earthquake alerting via SMS and email to defined stakeholders,
• providing a rapid preliminary assessment of the natural or human-made origin of seismic events,
• operation of a public, project-specific web page with real-time earthquake and background information,
• operation of a public-access archive of the recorded seismological data.

The Swiss Seismological Service at ETH Zurich (SED) is collaborating with the Federal Roads Office (FEDRO) to enhance seismic monitoring for the construction of the second tube of the Gotthard Highway Tunnel, which connects Göschenen, UR, and Airolo, TI. SED has recently deployed seven new seismic stations along the tunnel route to augment the capabilities of its automated seismological analysis system. This initiative aims to monitor both natural and mining-induced microearthquakes near the tunnel construction zones and the trajectories of the existing and new tunnel tubes, typically separated by approximately 75 meters. SED promptly provides FEDRO with earthquake alerts and comprehensive assessments for all detected seismic events, thereby contributing to the safe and efficient operation of tunnelling activities and highway traffic.

Scientists from the SED are working with local monitoring agencies from the region to build Earthquake Early Warning (EEW) across Central America. This multi-phase project is funded by the Swiss Agency for Development and Cooperation (SDC) at the Federal Department of Foreign Affairs (FDFA). In Phase 1 (2016-2017), SED worked with colleagues at INETER to evaluate the potential for EEW and to implement a prototype EEW system in Nicaragua. In Phase 2 (2018-2021), this prototype system was extended to include monitoring agencies in 3 additional countries - OVSICORI-UNA in Costa Rica, MARN in El Salvador, and INSIVUMEH in Guatemala. 70 EEW-ready strong motion accelerometers were purchased and deployed in the region. We further began to explore how a public EEW could be implemented, with EEW messages being integrated in the the emerging Digital-TV infrastructure as well as with a cellphone app developed within the project. In Phase 3 (2022-2024), we transition to operational EEW and public EEW messages using this cellphone app, and in the case of Guatemala City, an urban siren system. On 14 June 2023, the first public version of the cellphone app was released in Costa Rica.

The region suffers from large tsunamigenic earthquakes generated along the subduction zone, and also moderate crustal earthquakes that have in the recent past produced heavy damage, such as the M6.2 1972 earthquake that devastated Managua. The subduction zone events are often characterized by slow rupture velocity (the M7.7 1992 earthquake - the first slow earthquake ever documented - and most recently a M7.3 in 2014)

Earthquake Early Warning (EEW) is a tool that can rapidly characterize on-going earthquakes, and potentially provide seconds to 10s of seconds notification of impending strong shaking in advance of its occurrence. EEW can play an important role as part of a seismic risk reduction program, which is critical in the Central American region that has such a high seismic hazard. Additionally, making a seismic network capable of operating and maintaining an EEW system requires the network to achieve the highest standards in network performance - including station quality, speed and reliability of data communications, and robustness of the seismic network hub that runs the EEW software. Optimal network performance is also critical for other applications such as tsunami warning, volcano monitoring, and enables downstream scientific studies, eg on local Earth structure.

EEW can work in Central America because the seismic networks are relatively dense and data sharing is well-established and effective - necessary as earthquakes can have impacts beyond a single country. On 9 June 2016, just weeks after the first software was installed and before efforts to optimise had begun, a shallow M6.3 event occurred on the border with El Salvador that was detected by our system after 29s. Though far from the delay time required for operational EEW, this did demonstrate the promise of the existing infrastructure. With the current seismic network and optimised system, we typically can provide first EEW alerts within 8-12s for shallow on-shore earthquakes. This corresponds to a blind zone on the order of 20-30km around the epicenter where no advanced warning will be available. Outside the blind zone, for large earthquakes, this type of EEW can provide warning in advance of the strongest shaking for areas that will experience shaking of intensity VI on the Modified Mercalli Scale.  

Transfer of EEW capacity from SED to Central American Institutes is feasible because each agency use the same basic software for seismic network monitoring - SeisComP3 - that the SED itself relies on, and on top of which we have added EEW capability. SED use 2 standard algorithms to provide EEW - the Virtual Seismologist and the Finite Fault Detector. We also have been using the EEW Display (EEWD) to deliver desktop alerts to early adopters and testers.

California, Oregon, and Washington are currently implementing a public earthquake early warning (EEW) system, called ShakeAlert. To detect earthquakes and to generate alerts, ShakeAlert feeds data from the seismic and geodetic networks operated along the US West Coast into two algorithms: the point-source EPIC (formerly known as ElarmS and Onsite), and the finite-source Finite-Fault Rupture Detector (FinDer) algorithm. Alert messages from EPIC and FinDer are aggregated into a single alert feed.

ShakeAlert started in 2012 as a demonstration system for EEW and provided warnings of imminent strong ground shaking to a selected group of test users. At that stage, the Virtual Seismologist (VS; Cua and Heaton, 2009), implemented and tested by the SED, was part of the system. In 2013, California passed legislation to implement a public warning system. After the US Congress approved the funding in 2014, the transition to a public system started. A limited public roll-out of ShakeAlert started in California, Oregon, and Washington in the fall of 2018.  About one year later the testing of public alerting on mobile devices (phones) was rolled out in California. Washington, and Oregon followed in 2021. Alerts can be received as Wireless Emergency Alerts (WEA) on mobile devices, as well as through apps (e.g. MyShake, QuakeAlertUSA, and ShakeReadySD), or through a ShakeAlert-powered earthquake alert feature that is integrated into the Android Operating System.

The SED collaborates with the ShakeAlert team (US Geological Survey, Caltech, UC Berkeley, University of Washington, and University of Oregon) in the development,  implementation, and testing of FinDer (Böse et al., 2012; Böse et al., 2015; Böse et al., 2018; Böse et al., 2023).

The Mont Terri Rock Laboratory provides an underground infrastructure for conducting long-term experiments (years to decades) in clay rock, the Opalinus Clay, at a decametric to hectometer scale. This facility uniquely bridges the gap between typical laboratory experiments and pilot projects, incorporating the complexity of an in-situ setting while maintaining a high level of control over the experimental environment due to the extensive understanding of the clay formation.

SED, as partner in the Mont Terri Consortium, is active since many years in multiple experiments, as of principal investigator (*) or in partnership with other scientific and industrial organizations. The SED provides in-kind contributions as well as direct funding from European and/or national funding agencies. The projects cover a large variety of research topics, and often have an immediate applicability for industry.
Current experiments where the SED is involved are:

CL: CO2LPIE - CO2 Long-term Pulse Injection Experiment (2023-2028) examines the thermal, hydraulic, mechanical, and chemical (THMC) effects of CO2 injection into intact Opalinus Clay at in-situ conditions. It begins with a four-year phase, and could be extended over a decade. The goal is to improve understanding of caprock behavior and integrity, which is crucial for subsurface uses, particularly CO₂ storage. Insights into geochemical reactions are vital due to their impact on clay-rock composition and hydro-geomechanical properties. Accurate experimental data on reaction rates and barrier properties are essential for reliable reactive transport simulations, which are foundational for storage site characterization and long-term storage risk assessment.

CS-E (*): Mini-fracturing and Sealing (2021-2027) builds on the observations of the previous CS-D experiment (2018-2021). The primary objective is to understand the reactivation of individual, small fractures within the Mont Terri Main Fault. This involves a series of low flow rate, high pressure "mini-stimulations" to open pre-existing small fractures. The experiment aims to develop strategies to mitigate caprock failure during storage activities, and investigates on the use of sealants to be injected into the fault zone. It addresses critical research questions under geological conditions relevant to Switzerland, supporting the implementation of the Swiss national roadmap on carbon capture and storage.

FS-B: Imaging the long term loss of fault rock integrity (2015-2027) aims to image short-term fluid flow, permeability, and stress variations through a minor fault to evaluate the performance of radioactive waste repositories in shale. Its results can also inform CO₂ storage security and cap-rock integrity. FS-B involves repeated seismic imaging of fluid flow and stress variations during controlled fault activation by fluid injection, with continued monitoring afterward to characterize the permeability evolution of the stimulated fault.

FS-E: Distributed hydromechanical response during fault damage and fault self-sealing evolution (2023-2027). Using an unprecedented 10cm resolution distributed optical fiber method, the goal of the experiment is to explore the in situ time-lapse coupling of pore pressure, strain, and structures associated with the long-term sealing process following the fault zone activation (after the FS-B activation). Few studies have investigated the long-term hydromechanical behavior of a fault years after activation. FS-E results could also be used to assess the long-term integrity and security of host rocks and CO₂ storage.

GT: Gas transport models and the behavior of clay rocks under gas pressure (2022-2026). In geological waste repositories, gas is mainly generated by the corrosion of metals. The low permeability of clay rock can cause gas accumulation, increasing pressure and potentially fracturing the host rock. Waste processing or engineered gas transport systems are proposed as mitigation measures. In clay-rich formations, it is uncertain whether gas can escape without causing fractures and creating pathways for groundwater transport. Understanding these processes is incomplete, and a comprehensive mathematical framework is still lacking. The experiment includes both laboratory and field components.

PF-A: Progressive evolution of structurally controlled overbreaks - Long-term monitoring, hydromechanical simulation and rock testing (2023-2026).  From 2020 to 2023, the PF experiment investigated damage initiation and propagation in faulted Opalinus Clay rock above a large-diameter borehole. Initially, it examined the effects of ventilation and rock desaturation, followed by re-saturation. With the ongoing PF-A experiment the focus move on the long-term (3.5 to 7.5 years) evolution of rock mass damage and structurally-controlled over-breaks. Novel survey and monitoring techniques revealed reduced rock resistivities and subtle changes in seismic velocities, indicating evolving water flow paths linked to rock mass damage. Numerical simulations assessed the short-term mechanical behavior of the faulted rock mass. PF-A continues in-situ surveying and monitoring at a reduced frequency to establish long-term datasets. Advanced simulations aim to develop a 3D model for coupled flow and deformation phenomena, investigate subcritical crack growth effects on overbreaks, and validate a numerical model for predicting repository tunnel behavior in fractured rock.

ArtEmis will design, build, and operate a smart and scalable multi sensor system comprising of about 100-200 novel low-cost geochemical sensors, that will measure with unprecedent spatial and temporal resolution changes in radon concentration in ground water, together with other observables like temperature and acidity.

In recent years, we have developed efficient geophysical and seismological measurement tools that enable the characterization of instabilities based on their vibrational behavior and are suitable for monitoring. New methods for the characterization of rock instabilities in terms of extent, volume, and condition, have been developed along with a derived classification and corresponding measurement strategies. Additionally, continuous long-term observations with seismometers have been developed. In the future, such tools will increasingly contribute to quantifying the risks of spontaneous and earthquake-induced instability failures and complement conventional techniques.

Currently, real-time monitoring of instabilities is the only way to provide continuous information for risk assessment and early warning before an event occurs. With seismic monitoring, we are able to monitor the internal properties (stiffness, vibration behavior, amplification, damping, vibration polarization) of the instability with a very high precision. This new component could become standard practice due to its high sensitivity to changes in slope characteristics. The combination of our monitoring, seismic site characterization, integration of deformation measurements and environmental data, and numerical modeling will provide insights into the driving factors of slope failure, and contribute to hazard and risk assessment of unstable slopes.

The aim of this applied project is the national implementation of the developed methods. The work includes the practical continuation of existing measurement sites in order to apply the methods in practice. Our contribution will show how vibration measurements can be used in the future to quickly characterize potential slope instabilities in terms of extent, volume and condition, and how the interpretation can contribute to the optimal placement of measuring systems (seismic, GNSS, total station, etc.).

If a spectral microzonation study is published by the responsible authority, this must be used to determine the site-specific earthquake impact in accordance with the Swiss standard SIA 261. Accordingly, the response spectra based on the microzonation study published in 2009 were previously used in the canton of Basel-Stadt and in parts of the canton of Basel-Landschaft. With the revision of the SIA 261 and SIA 261/1 standards published in 2020, there was reason to review and update the existing microzonation study. In addition, numerous new observation data and reference data have been collected since 2009. The findings can be applied in a microzonation study.

The cantons of Basel-Stadt and Basel-Landschaft have therefore decided to launch a project to revise the microzonation. This microzonation is based on implementation and extension of the amplification models from the work in the Basel earthquake risk model project (2018-2024). The procedure for determining the microzones and their elastic response spectra corresponds to that of the SIA261/1 standard. The microzones are defined with the help of geological and geophysical data. Particular care is taken to ensure that the uncertainties in the models are not too large. For this reason, temporary seismic stations were installed in areas with large uncertainties in the amplification models. Geophysical investigations are also planned. The application of microzonation is simplified by limiting the number of microzones. This is done by combining areas with similar amplification of the earthquake waves. Possible earthquake-induced phenomena will be mapped in analogy to the reference maps of the 2009 microzonation. The project is being carried out in collaboration with the Applied Geology Group (AUG) of the University of Basel, the Chemical and Biosafety Control Authority and the Department of Justice and Security of the Canton of Basel-Stadt, and the Department of Construction and Environmental Protection of the Canton of Basel-Landschaft.

The forth phase of this project is split into 3 subtasks with the main goal to improve regional and local seismic hazard assessment in Switzerland; with particular focus to the sites of potential regions of nuclear repositories. These sub-projects are:

The focus of sub-project 1 lies in the development and improvement of earthquake ground-motion attenuation and source-scaling models for Switzerland. We target ground-motion estimates for sites in the near field (at the soil surface and at depth) for damaging events; we also target smaller induced earthquakes. The work is based on observations in Switzerland and Japan. Studying the near-surface amplification and attenuation constitutes a key point in our research.

The scope of sub-project 2 is to improve deterministic predictions of ground motion, especially concerning near-field, nonlinear behavior in sedimentary rocks and soft soils, and new approaches for modelling complex source processes. This includes the calibration of material parameters via field measurements and the development of numerical codes to simulate ground motion in three-dimensional complex media. The results of subproject 1 will be linked to deterministic simulations from Subproject 2, and the results will be tested and compared to observed data.

In sub-project 3, the aim is to develop a time-dependent earthquake forecasting model which during an ongoing seismic crisis can answer questions related to the probability of the occurrence of large earthquakes in the near future. This includes the development and testing of a model de-scribing the time-dependent seismic hazard, the establishment of communication products that translate the model output into useful information for ENSI, and the assessment of the applicability of earthquake early warning in Switzerland.

Geophysical and seismological tools have advanced in recent years, enabling the study of slope instabilities with more precision. These tools analyze the vibrational behavior and earthquake response of slopes, which can provide valuable information about their stability. However, while these tools can detect, map, and monitor potentially instable slopes, there is still limited understanding of the influence of environmental conditions on their seismic behavior.

To address this gap in knowledge, this project aims to investigate the relationship between environmental factors and slope stability. We will perform repeated short-term field measurements and continuous monitoring to focus on examining the relationship between temperature, precipitation, groundwater levels and permafrost on the vibrational behavior of instabilities. These insights can then be used to classify instabilities and understand their movement and behavior.

The project findings aim to significantly impact the prevention of human casualties and damage to infrastructure, as well as cultural and natural heritage, caused by landslides. A better understanding of the influence of environmental factors on the seismic signature of slopes and slope behavior will enhance hazard analysis and risk assessment. This, in turn, will help to protect communities and infrastructure in areas directly or indirectly threatened by landslides.

This working group gathers the researchers with competences in site characterization in order to discuss and improve the work performed in different projects, especially for sites with new permanent seismic stations. The available tools for processing, archiving and disseminating are shared within the group. The group is responsible for setting up and updating the SED database for site characterization. The group meets regularly to discuss new results and to review the work before it is published.
So far, the group performed more than 250 ambient-vibration seismic array and MASW measurements, about 7000 single station horizontal-to-vertical spectral ratio measurements to determine the resonance frequencies of the soils, and 10 seismic cone penetration tests (SCPT) to assess the risk of potential liquefaction during earthquakes. Temporary seismic stations are also installed and managed to derive empirical amplification functions at sites of interest.

Settlements only few hundred meters apart can be affected at significantly different levels by the same earthquake. The cause is the local earthquake response, or site amplification, which is determined by the type of soil (e.g. soft sediments or stiff rock) but also by its geometry (a wide plain or a sedimentary basin). In this perspective, the alpine valleys are peculiar geological environments, as the thickness of the sedimentary infill increase from few meters at the borders of the valley to several hundred meters at its centre; this setting determines distinctive earthquake response effects. Besides, valleys are not marginal from the risk point of view, as they can be densely populated and host critical infrastructure for the transport of goods and people across the alpine arch.
In 2019, the Earthquake working group of the SIA 261 commission has therefore recommended the execution of a baseline study on the topic of earthquake local response in alpine valleys. later included in the federal measures for earthquake risk management (BAFU, 2020). This research project directly addresses such recommendation; it aims i) at a systematic investigation of amplification effects of seismic waves in the alpine valleys of Switzerland and ii) at the development of a proposal for their consideration in the next revision of the SIA 261 building code.

This is the 1st subproject of the “ENSI – SED-Erdbebenforschung zu Schweizer Kernanlagen” project.

This subproject aims to improve source-scaling and attenuation models and to develop methods for the prediction of strong ground motion in Switzerland both at the surface as well as at depth. Two main approaches are investigated: ground motion prediction equations (GMPEs) and stochastic simulation models. Both approaches require adaptions to the local seismicity and careful consideration of their calibration to Swiss conditions. The Fourier spectral and stochastic models correspond to the current state of research and have some advantages over the empirical attenuation relationships, as it is possible to adjust the model to specific local site conditions. The complete understanding in terms of physical parameterization of such models is crucial in order to decouple different effects, which allow building robust predictive models that scale appropriately to large magnitude events. In this regard, variability in source parameter such as stress drop and corner frequency is crucial. Similarly, variability in site-related attenuation parameter kappa (local intrinsic and scattering attenuation) is also need to be well understood. Developed stochastic and duration models from Japanese data allow the review of the Swiss model for large magnitudes in the different distance ranges and at various rock sites which have, as yet, not been instrumentally recorded in Switzerland. The local weak-to-moderate seismicity is used to calibrate the predictive models. The long-term goal is to develop an improved stochastic simulation model for Switzerland allowing existing uncertainties to be rigorously evaluated and reduced. In future, such models will also allow an assessment of ground motion caused by induced seismicity due to the activation of existing fractures and/or the generation of new fractures. Moreover, we developed, validated, and applied a physics-based stochastic model to characterize high-frequency ground motion at depth in the Fourier domain. The goal of it is to be able to predict future ground motions at deep geological disposals.