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The so-called site effects caused by superficial geological layers may be responsible for strong ground motion amplification in certain configurations. We focus here on the industrialized Tricastin area, in the French Rhône valley, where a nuclear site is located. This area lies above an ancient Rhône Canyon whose lithology and geometry make it prone to site effects. This study presents preliminary measurements to investigate the local seismic amplification. We deployed three seismic stations in the area for several months: two stations were located above the canyon, the third one was located on a nearby reference rock site. The recorded seismicity was analysed using the Standard Spectral Ratio technique (SSR). The estimated amplification from weak motions reaches a value of 6 for some frequencies. These first results confirm the possibility of estimating seismic amplification using earthquakes recorded for less than one year, in this highly anthropogenic and industrialized environment, despite the local low-to-moderate level of seismicity. Noise-based SSR, that presents an obvious interest in such seismic context, shows also promising results in the area. To complement this empirical approach, we estimated the amplification using 1D wave propagation modelling. This numerical estimate is based on shear wave velocity profiles resulting from geophysical characterization campaigns. Comparison of the two approaches at low frequency, where numerical estimate is considered as the most representative, tends to suggest that edge-generated surface waves may have a strong influence in the local seismic response. This interpretation will be further investigated in the future.

A series of reclamation works that took place during the twentieth century, almost completely destroyed the dune system that characterized the eastern part of the Grado-Marano perilagoonal area (NE Italy). Because of the limited data available, so far very little was known about the local subsurface conditions and the present paper presents the main outcomes of the seismic exploration accomplished with a twofold goal: collecting comprehensive data about the subsurface conditions (which geologists need to be able to reconstruct the formation processes of the local geomorphological elements) and testing a series of efficient and unconventional methodologies based on the analysis of surface waves from both active and passive seismic data. The survey was designed and accomplished also considering the local digital terrain model (DTM) and some resistivity and penetrometer data. In the present paper we focus on three main areas and, from the methodological point of view, special emphasis is given to the Holistic analysis of Surface waves (HS) and the Horizontal-to-Vertical Spectral Ratio (HVSR), since both these techniques require simple field procedures and a light equipment. It is also show the wealth of information that the simple spectral analysis of multi-offset passive data can provide in particular for the identification of possible lateral variations. In fact, in spite of the low-energy depositional environment, the area reveals extremely complex with major and abrupt lateral variations that require special care and prevent from using coarse methodologies that cannot properly handle their identification. Collected geophysical data provide a consistent overall scenario: while the area is in general dominated by soft (silty) sediments, the residual dunes are constituted by cemented sandy materials (medium-grained calcarenite) responsible for anomalously high shear-wave velocity (VS) values already at the surface. Parallel to such residual sandy dunes we also identified a series of peat channels characterized by distinctive low VS values due to a significant amount of organic components.

An efficient system for the joint acquisition and analysis of multi-component active and passive seismic data is presented. It is shown how, in spite of the limited field equipment (the system requires just a 4-channel seismograph, one 3-component and four vertical-component geophones), it is nevertheless possible to define up to seven different (but mutually related and complementary) objects used to constrain a multi-objective joint inversion capable of providing a robust subsurface shear-wave velocity (VS) profile for both geotechnical and seismic-hazard studies. The presented approach relies on acquisition techniques that require simple and straightforward field procedures useful in particular, but not solely, in the characterization of urban and remote areas where, due to logistical problems, standard acquisition procedures cannot be easily applied. Active data recorded by a single 3-component geophone are processed so to define up to five objective functions: the group-velocity spectra of the three components, the radial-to-vertical spectral ratio and the Rayleigh-wave particle motion frequency curve. Passive data are used to compute two further objects: the horizontal-to-vertical spectral ratio and the phase-velocity dispersion curve obtained via miniature array analysis of microtremors. These seven objects are jointly inverted by means of a multi-objective inversion procedure based on the Pareto criterion. Performances are assessed through a comprehensive field dataset acquired in an urban area of NW-Italy. The consistency of the overall procedure is assessed by comparing the results with the analyses accomplished by considering classical multi-channel active and passive data and methodologies (multi-component MASW, multichannel analysis of surface waves and ESAC, extended spatial auto-correlation).

Studies regarding site characterization are critical to determine the feasibility and model of infrastructure that can be built in an area. One method that is very reliable in site characterization is Multichannel Analysis of Surface Waves (MASW). This method utilizes surface wave (S-wave) propagation to identify the subsurface. Therefore, in this research, an infrastructure assessment was carried out in the North Morowali Regency area using the MASW method. Based on the results of the shear wave velocity profile (Vs), the research area is dominated by clay to dense sand. Therefore, it is highly recommended that the infrastructure model built in the North Morowali area be adapted to the conditions of the sites that dominate the area so that the buildings to be built will last a long time.

Passive surface wave methods are non-invasive, low-cost, and robust approaches to image near-surface shear-wave velocity (Vs) structure using passive seismic sources. A clean and high-resolution dispersion image is critical for surface wave analysis. In practice, however, artifacts or aliasing are almost inevitable in passive surface wave dispersion measurements and seriously pollute the measured dispersion spectra. It is significant to clarify how they are generated, how they affect the dispersion measurement, and how they can be attenuated. We provide the first comprehensive review on artifacts that are frequently observed in high-frequency (>1 Hz) passive surface wave dispersion measurements and summarize them into two general groups: geometry-related artifacts and source-related artifacts. Mathematical derivations and numerical as well as field examples are presented to explain the underlying physics of various artifacts and explore potential solutions and guidelines to attenuate them before and after field observations. This work will help the reader understand the complexity of the measured dispersion spectra and lead to improvements on rapidly advancing passive surface wave methods.

As global warming continues, the Earth's cryosphere is experiencing severe degradation. This study leverages a novel combination of distributed acoustic sensing (DAS) and artificial intelligence to monitor and decipher cryospheric dynamics. We have developed an advanced time‐lapse surface wave analysis workflow to capture shear wave velocity changes (Δv)$({\\Delta }v)$during a 2‐month controlled permafrost thaw experiment in Fairbanks, Alaska. To understand the underlying physical mechanisms of Δv${\\Delta }v$ , multimodal rock‐physics simulations were conducted to associate the observed Δv${\\Delta }v$to hydrological and thermal processes like heating and rainfall events. Furthermore, we employ a physics‐guided deep learning algorithm alongside interpretable techniques to evaluate the impact of various physical factors and shed light on the cryospheric hydro‐thermo coupling mechanisms. This study highlights the potential of using DAS and data‐driven rock‐physics simulation for complex cryosphere monitoring and offers a comprehensive view of the permafrost's thawing dynamics. Plain Language Summary Our study delves into the changes in the cryosphere due to global warming, utilizing an instrumented field site in Fairbanks, Alaska. We used Distributed Acoustic Sensing (DAS), which involves sending light pulses through fiber‐optic cables to detect ground vibrations, to provide insights into the condition of the permafrost. Using data previously collected over a 2 months period, we analyzed the permafrost's response to artificial warming, akin to the effects of climate change. This process involved tracking shear wave velocity changes in the ground, which helped identify the shifts in ice, water, and soil composition within the permafrost. Our findings indicate that permafrost thawing significantly alters shear wave velocity, signaling changes in the structure and water content of the cryosphere. By integrating field observations with computer simulations and deep learning, we unraveled the complex hydro‐thermo interactions within the thawing cryosphere. This research is helpful for understanding how the transformation of the cryosphere affects global climate and local ecosystems, enhancing our capability to predict and manage the ramifications of climate change in Earth's frozen regions. Key Points DAS observes seismic responses related to hydrological and thermal processes within the cryosphere Time‐lapse surface wave analysis delivers high‐resolution shear wave velocity changes within the permafrost Data‐driven rock‐physics simulations predict seismic velocity perturbations and reveal complex hydro‐thermo coupling mechanisms

The strong ground motion effect is amplified or de-amplified due to the change in subsoil condition. Local soil properties prediction is critical for earthquake-safe areas and the earthquake hazard assessment of existing structures. This study was carried out with time-domain 1D Nonlinear analysis to understand the soil response characteristics of the Arifiye district. In this sense, geotechnical drilling at 47 points and surface wave analysis at 44 points were performed. Site response profiles in the study area were analyzed with the DeepSoil program for Mw:7.0 1967 Mudurnu and Mw:7.4 1999 Kocaeli earthquake scenarios. Peak spectral acceleration (Pga) and spectral acceleration (Sa) values were determined in the analysis of the Mudunu scenario as 0.11–0.24 g and 0.44–1 g, respectively. The Kocaeli scenario’s Pga and Sa distribution were obtained in a wide range of 0.2–0.56 g and 0.47–2.3 g, respectively, compared to the Mudurnu scenario. Especially in the Mw:7.4 model, high Pga (> 0.3 g) and Sa (> 1 g) values were obtained in the uncemented units located north of the study area. Kocaeli scenario results showed that the spectral accelerations at the surface in soil groups D and E were higher than the Turkish Building Earthquake Code building requirements. It is necessary to update the earthquake design spectra site-specific. The results clearly showed the effect of ground conditions and strong ground motion selection on earthquake-resistant building design.

In earthquake engineering, the precise characterization of long-period ground motion in the form of surface waves (Love and Rayleigh type) is crucial for designing resilient structures, particularly in complex environments such as sedimentary basins. This study evaluates the efficacy of the Normalized Inner Product (NIP) method for estimating surface wave parameters using limited input data within seismic analyses conducted based on numerical simulations. The method is benchmarked against two established techniques–Six Degrees-of-Freedom Polarization Analysis (6C-Pol) and Multiple Signal Classification (MUSIC)–to evaluate its precision in parameter identification. As an example, the methodologies are first applied to analyze surface waves from synthetically generated signals and then from basin-induced surface waves coming from a simplified basin with known characteristics, employing the the spectral element code SEM3D for 3D wave propagation simulation. The results revealed that the NIP method efficiently estimated surface wave characteristics using minimal information, demonstrating its efficiency. Furthermore, due to its capacity to rapidly process large datasets, the NIP method effectively quantified basin-induced surface waves across the basin surface, offering a robust framework for a more comprehensive understanding of 3D basin effects.

Active fault detection has an important significance for seismic disaster prevention and mitigation in urban areas. The high-density station arrays have the potential to provide a microtremor survey solution for shallow seismic investigations. However, the resolution limitation of the nodal seismometer and small-scale lateral velocity being inhomogeneous hinder their application in near-surface active fault exploration. Distributed acoustic sensing (DAS) has been developed rapidly in the past few years; it takes an optical fiber as the sensing medium and signal transmission medium, which can continuously detect vibration over long distances with high spatial resolution and low cost. This paper tried to address the issue of near-surface active fault exploration by using DAS. We selected a normal fault in the southern Datong basin, a graben basin in the Shanxi rift system in north China, to carry out the research. Microtremor surveys across the possible range of the active fault were conducted using DAS and nodal seismometers, so as to obtain a shallow shear wave velocity model. Meanwhile, we applied a Brillouin optical time domain reflectometer (BOTDR) and distributed temperature sensing (DTS) to monitor the real-time fluctuation of ground temperature and strain. Our results show that the resolution of the deep structures of the fault via the microtremor survey based on DAS is lower than that via the seismic reflection; whereas, their fault location is consistent, and the near-surface structure of the fault can be traced in the DAS results. In addition, both the BOTDR and DTS results indicate an apparent consistent change in ground temperature and strain across the fault determined by the DAS result, and the combination of surface monitoring and underground exploration will help to accurately avoid active faults and seismic potential assessment in urban areas.

While geodetic measurements have long been used to assess landslides, seismic methods are increasingly recognized as valuable tools for providing additional insights into subsurface structures and mechanisms. This work aims to characterize the subsurface structures of the deep-seated gravitational slope deformation (DSGSD) at Heinzenberg through the integration of active and passive seismic measurements. Seismic techniques can hereby deliver additional information on the subsurface structure and mechanisms involved, e.g., the degree of rock mass degradation, the resonant frequencies of the potentially unstable compartments, and the local fracture network orientations that are influenced by wavefield polarization. By employing advanced methods such as H/V analysis, site-to-reference spectral ratios, polarization analysis, surface wave analysis, and the joint multizonal transdimensional Bayesian inversion of velocity structures, we establish a comprehensive baseline model of the landslide at five selected sites. This baseline model shall help identify potential changes after the refilling of Lake Lüsch, which started in 2021. Our results reveal the rupture surface of the DSGSD at various depths ranging from 30 m at the top to over 90 m in the middle of the slope. Additionally, we estimate key parameters including the shear wave velocities of the different rock masses. The 2D geophysical profiles and rock mass properties contribute to the understanding of the subsurface geometry, geomechanical properties, and potential water pathways. This study demonstrates the significance of integrating seismic methods with traditional geodetic measurements and geomorphologic analysis techniques for a comprehensive assessment of landslides, enhancing our ability to monitor and mitigate hazardous events.