Ambient Seismic Noise Research Articles

3-D body-wave tomography from the seismic ambient noise recorded by a dense array in the Dehdasht area, Iran

SUMMARY The strong attenuation of the thick sedimentary layers in the Dehdasht region, Iran, renders active seismic exploration surveys difficult. The imaging of the existent limestone reservoirs is limited to the shallow subsurface due to the strong attenuation of seismic waves. Here, we discuss a different approach to imaging the subsurface using body waves extracted from the cross-correlation of the seismic ambient wavefield. We discuss the technical challenges to extracting clear P-wave arrivals from the seismic ambient wavefield of a dense 3-component seismic array deployed in the Dehdasht basin. We invert the data for the 3-D P-wave velocity structure and compare the velocity model with results from the 2-D active seismic surveys in the area. The results show the potential of using body waves extracted from the seismic ambient wavefield for imaging purposes in highly attenuating areas.

A look at the blind Kumamoto experiment: combining active and passive seismic observations to avoid Rayleigh-wave mode misidentification

We present our pathway through participation in the blind Kumamoto exercise, particularly the Step 1 of site characterization. The combination of passive and active seismic imaging techniques is used to image the velocity profile beneath the KUMA site. The estimation of the broadband Rayleigh wave dispersion curve is based on cross-correlations of ambient seismic noise and analysis of active seismic shots. We calculate correlations from the entire time series (only vertical components) of each seismic array after classical pre-processing of ambient noise data. Then, a passive seismic section is constructed using all available stations pairs and stacking the cross-correlation traces with similar interstation distances. The obtained passive seismic section is analyzed using a high-resolution Radon transform to obtain the dispersion image of Rayleigh waves traveling through the KUM-LL, KUM-M and KUM-SM arrays. Then, the information is merged and interpolated to obtain the final broadband dispersion curve. In addition, active source seismic data are used with the high-resolution Radon technique to constrain the model at shallow depths (< 30 m). Then, a broadband dispersion image is constructed with significant energy from 0.9 Hz to 45 Hz. The final dispersion curve is inverted using the non-linear neighborhood algorithm. Using just the fundamental mode Rayleigh wave, a first model with normal velocity variation in depth is obtained that corresponds well with the preferred model provided by the organizing committee. The addition of a mHVSR curve in a joint inversion better constrains the deeper part of the model (> 1 km). After comparison of the submitted dispersion curve to the theoretical dispersion curve for the preferred model (Step 4 of the blind test), the authors note that there was a clear misinterpretation in the fundamental mode of their submitted results, especially at frequencies higher than 5 Hz. Using both fundamental (only visible in the passive data set) and first overtones of Rayleigh waves (only visible in the active seismic data set) a refined velocity model could have been inferred, but we decided to keep our first submitted result. This detailed interpretation should be further studied as dispersion images from forward and backward hammer shots are quite different, which may indicate strong variations in the geometry and/or shear-wave velocities of the first meters of the subsurface.Graphical

Classifying urban areas from learned acoustic and seismic data

In this work, a deep transfer learning algorithm is used to classify different urban areas from acoustic and seismic data. The deep transfer learning model combines Google’s deep learning model AlexNet. Measurements of acoustic and seismic ambient noise were conducted in an urban environment. The urban acoustic and seismic measurements are heavily influenced by traffic noise but exhibit more variation with respect to urban location due to the influence of subsurface conditions. A K-means clustering analysis is employed on the acoustic and seismic spectrogram to classify the urban areas. The results demonstrate that seismic and acoustic data can have similar cluster centroid locations in the frequency band of 4 Hz–10 Hz. The transfer learning results will be presented and discussed.

Microseisms as a Tool for Geophysical Research. A Review

Considering seismic ambient noise as a tool for geophysical research, the spatial and temporal characteristics of the noise itself are of a great interest. Characterization of energy and frequency distributions of the microseisms is an important stage of the research. The review considers the main mechanisms of generation of microseismic oscillations in a wide frequency range, including primary and secondary microseisms (0.05–0.3 Hz), low-frequency oscillations (0.2–50 mHz), high-frequency oscillations (2–60 Hz), lake microseisms (0.5–2 Hz). The paper also describes the most popular techniques used for processing and analyzing a continuous data of seismic ambient noise; a wide range of geophysical problems was demonstrated, which use the results of seismic monitoring.

Characterizing Ambient Seismic Noise in an Urban Park Environment.

In this study, a method for characterizing ambient seismic noise in an urban park using a pair of Tromino3G+ seismographs simultaneously recording high-gain velocity along two axes (north-south and east-west) is presented. The motivation for this study is to provide design parameters for seismic surveys conducted at a site prior to the installation of long-term permanent seismographs. Ambient seismic noise refers to the coherent component of the measured signal that comes from uncontrolled, or passive sources (natural and anthropogenic). Applications of interest include geotechnical studies, modeling the seismic response of infrastructure, surface monitoring, noise mitigation, and urban activity monitoring, which may exploit the use of well-distributed seismograph stations within an area of interest, recording on a days-to-years scale. An ideal well-distributed array of seismographs may not be feasible for all sites and therefore, it is important to identify means for characterizing the ambient seismic noise in urban environments and limitations imposed with a reduced spatial distribution of stations, herein two stations. The developed workflow involves a continuous wavelet transform, peak detection, and event characterization. Events are classified by amplitude, frequency, occurrence time, source azimuth relative to the seismograph, duration, and bandwidth. Depending on the applications, results can guide seismograph selection (sampling frequency and sensitivity) and seismograph placement within the area of interest.

Crustal velocity images of northwestern Türkiye along the North Anatolian Fault Zone from transdimensional Bayesian ambient seismic noise tomography

SUMMARY Türkiye poses a complex crustal structure and tectonic settings owing to the northward convergence of the Arabian and African plates with respect to the Anatolian and Eurasian plates. A reliable 3-D crustal structure of the unruptured segment of the North Anatolian Fault Zone (NAFZ) in the Sea of Marmara is thus of utmost importance for seismic hazard assessments considering that the megacity Istanbul—with more than 15 million habitants—is close to this seismic gap. This study provides high-resolution shear wave velocity images of northwestern Türkiye, including the NAFZ, revealed from ambient seismic noise tomography. We extract over 20 000 Green’s functions from seismic ambient noise cross-correlations and then construct group velocity perturbation maps from the measured group delays with a transdimensional Bayesian tomographic method. We further perform an S-wave velocity inversion to image depth-varying velocity structures. Our high-resolution data allowed us to image S-wave velocities down to 15 km depth and reveal weak crustal zones along the NAFZ, as indicated by low shear wave velocities. We find a low-velocity zone along the Main Marmara Fault, linked with aseismic slip and a deep creep mode. Furthermore, we identify a high-velocity anomaly associated with the unruptured section that defines the boundaries of the locked zone in the crust, which can potentially trigger a destructive earthquake in the future.

Soil-building resonance effect in the urban area of Villa d’Agri (Southern Italy)

This study aims to evaluate the possible occurrence during seismic shaking of interaction effects between the shallow subsoil and the overlying buildings of the Villa d’Agri town (Southern Italy). From the geological and building heritage points of view, the investigated area represents a typical town along the Apennines chain and therefore the obtained results could be easily exported to similar urban areas. A total of 239 single-station seismic ambient noise measurements were thus performed, 154 on the urban soils and 85 within buildings. Both subsets of measurements were planned to cover the main outcropping lithologies and building typologies. By means of the Horizontal-to-Vertical Noise Spectral Ratio technique, isofrequency and isoamplitude maps have been reconstructed for the whole area. The results evaluated on the 65 tested buildings allowed to infer the empirical relationship between the first vibrational period, T(s), and their height, H(m). Using this relationship and available information on the height of each building, the first vibrational frequency was estimated for 659 buildings belonging to the urban area of Villa d'Agri. Finally, in order to assess the possible occurrence of the double resonance phenomenon, we compared the main frequency of each building with that interpolated for the underlying foundation soil. The results show that the probability of being affected by the double resonance effect is very high only for a couple of buildings, high for about 16% of the buildings, moderate for the 23% and practically null for most buildings (60%).

Seismic Attenuation Extraction From Traffic Signals Recorded by a Single Seismic Station

AbstractSeismic ambient noise contains rich information about the physical properties of the critical zone. From the motor vehicle noise, we extract the daily seismic attenuation by quantifying the linear relationship between the frequency and amplitude ratio of paired instantaneous spectra. After verifying the reliability of the proposed method, we apply it to seismic ambient noise data collected at three urban sites. The estimated attenuation is compared against three environmental variables: rainfall, temperature, and traffic volume. The results show that the estimated seismic attenuation correlates most strongly with precipitation with positive time lags, suggesting a high attenuation sensitivity to changes in soil moisture and groundwater system. Furthermore, differences in attenuation‐precipitation correlations indicate that near‐surface physical properties may vary significantly due to local site conditions. Our statistical method extracts reliable near‐surface information from highly complex urban ambient noise data, achieving unprecedented spatial and temporal resolution compared to existing ambient noise imaging methods.

Rayleigh wave spectral distortions induced by an anticline structure

SUMMARYSpectral anomalies in the seismic ambient noise are commonly observed above hydrocarbon reservoirs at frequencies of several Hertz. If properly understood, these anomalies could be a potential indicator for hydrocarbon reservoir exploration or monitoring. Under the assumption that ambient noise mainly consists of surface waves, previous studies showed that the geological structure, rather than the hydrocarbon content, could be the major cause of the observed anomalies for purely elastic waves. This work further explores how Rayleigh waves interact with an anticline structure, a typical geological trap for a hydrocarbon reservoir. We propose an approximate semi-analytical surface wave approach for modelling the spectral anomalies. It is based on the contribution of 1-D local solutions from two different models. The results are compared with those obtained via 3-D numerical simulations using the spectral-element approach in the case of a wavefield dominated by Rayleigh waves. Analysis of the anomalies generated by an anticline structure is performed for different source configurations. It shows that the semi-analytical method provides reasonable spectrum predictions for smooth layered models and under some restrictions on the source distribution. Such a tool allows us to run a larger number of simulations to explore the parameter space and finally provide a general law linking the anticline geometrical parameters and the elastic properties of the medium to the anticline-induced spectral anomaly for the case of fundamental mode Rayleigh waves.

New constraints on the seismotectonics and crustal structure of the Eastern Trans-Mexican Volcanic Belt based on local seismicity, focal mechanisms and a preliminary state of stress evaluation

After the occurrence of unusual upper crustal seismic activity within the eastern sector of the Trans-Mexican Volcanic Belt (TMVB) in 2019, an area of generally low seismicity, an effort was made to interpret the origin. Concerns leading to the careful analysis presented here, were manifold: Shallow clustered seismicity can indicate active volcanism or related processes, as well as hydrothermalism. Additionally, the area was struck by a major earthquake (Mw 6.4) on January 4, 1920, which had devastating effects on the area's complex geological features and caused hundreds of deaths and significant material damage. As a result, several events of the 2019 sequence of unusual seismic activity have been relocated to precisely know the location. The 34 earthquakes of the 2019 seismic sequence occur in a relatively small area of less than 1600 km2. The seismic sequence can be further subdivided into 2 clusters, separated by the Pico de Orizaba – Cofre de Perote volcanic chain, which itself separates two tectonostratigraphic terranes, is a topographic divide and represents the limit to a considerable topographic drop. We also used the seismic sequence to constrain further the state of local stress and henceforth observe the tectonic regime of the area. For this purpose, focal mechanisms of the events with Mc > 4 (this sequence and previous data) were determined and the inversion of the stress tensor of this group was carried out. Similarly, the state of stress for the central zone of the TMVB was recalculated to establish its possible variations towards the eastern part of the TMVB. We show that the state of stress of the Eastern/Easternmost TMVB presents a transtensional regime, similar to the central TMVB, which has been suggested is mainly caused and controlled by the geometry of the subduction of the Cocos plate beneath the North American plate. A review of Rayleigh wave dispersion curves, calculated through interferometry of ambient seismic noise, a change is observed that suggests some variation in the structure of the eastern and easternmost areas. This contribution is relevant because little is known about the seismotectonics of the TMVB's eastern sector, in part because of the low cortical seismicity reported along the TMVB, the reduced coverage of seismic stations in this region and the distance from the trench Middle American Trench (MAT), where most of the important tectonic processes in Mexico take place. Recently, with the incorporation of a regional seismic network, the detection of small-magnitude events in the study area has significantly been improved.

Quantifying Urban Activities Using Nodal Seismometers in a Heterogeneous Urban Space.

Earth's surface is constantly vibrating due to natural processes inside and human activities on the surface of the Earth. These vibrations form the ambient seismic fields that are measured by sensitive seismometers. Compared with natural processes, anthropogenic vibrations dominate the seismic measurements at higher frequency bands, demonstrate clear temporal and cyclic variability, and are more heterogeneous in space. Consequently, urban ambient seismic fields are a rich information source for human activity monitoring. Improving from the conventional energy-based seismic spectral analysis, we utilize advanced signal processing techniques to extract the occurrence of specific urban activities, including motor vehicle counts and runner activities, from the high-frequency ambient seismic noise. We compare the seismic energy in different frequency bands with the extracted activity intensity at different locations within a one-kilometer radius and highlight the high-resolution information in the seismic data. Our results demonstrate the intense heterogeneity in a highly developed urban space. Different sectors of urban society serve different functions and respond differently when urban life is severely disturbed by the impact of the COVID-19 pandemic in 2020. The anonymity of seismic data enabled an unprecedented spatial and temporal resolution, which potentially could be utilized by government regulators and policymakers for dynamic monitoring and urban management.

Integrated geophysical and geological surveys reveal new details of the large Montescaglioso (southern Italy) landslide of December 2013

A methodological approach based on the integration of different survey techniques may be particularly suitable for the study of areas with complex geology such as those affected by landslide phenomena. The results obtained by the application of combined electrical resistivity tomography (ERT) technique, ambient seismic noise measurements (single station and array), geological investigation and granulometric analysis to characterize and study a landslide occurred on December 3rd, 2013 in Basilicata region (southern Italy) are presented and discussed. The landslide partially affected the peri-urban area of Montescaglioso town and caused damages to small-medium enterprises, infrastructures, and housing. The analysis of ambient noise signals made possible to estimate the depth of the contacts between the main geological formations outcropping in the area and revealed the existence of directional resonance effects. The discontinuities observed by the ERT have confirmed the presence of different lithotypes and allowed illuminating the sliding surface at a depth of about 40 m in agreement with the seismic results and boreholes data. The shallow discontinuities inferred from geophysical surveys were supported also by the results of a detailed granulometric analysis performed on a geognostic survey, confirming the presence of a heterogeneous sedimentary deposit in the area. In such complex context, the acquisition of spatially distributed geophysical properties permitted to increase the knowledge of the geological setting of the area, reaching a level of detail that cannot be observed by applying only a sparse discrete direct sampling. The integration of all the obtained information allowed the delineation of geophysical discontinuities related to the presence of sliding or weakness surfaces and areas with high water content that could contribute to future activation of the movement. This information was crucial to better understand the nature of the landslide, contributing to the planning and the implementation of risk mitigation actions and to the design of remediation works.

The Seismic Signature of California's Earthquakes, Droughts, and Floods

AbstractThis study investigates changes in seismic velocities in the period 1999–2021 using about 700 permanent and temporary broadband seismic stations in the state of California. We compute single‐station cross‐correlations of the ambient seismic noise and use the coda‐wave interferometry to measure the changes in seismic velocities (dv/v) using a stretching technique. We focus on the 2–4 Hz frequency band and the upper 500 m of the near‐surface sensitivity. We discuss dv/v within the context of nonlinear elasticity. We fit models of thermoelastic strains, various hydrological models that diffuse rainwater, and slow‐dynamics healing models for the postseismic response of earthquakes. In general, we find that both thermoelastic strains and hydrological strains have a similar amplitude of impacts on dv/v. We find that the diffusion of rainwater using a drained response in a poroelastic medium explains most of the data. The best fit hydraulic diffusivity is high in the mountains and low in the basin. We find that the largest drop in seismic velocity occurs during the 2004–2005 wet winter and that the 2011–2016. Drought is characterized by a multiyear marked increase in dv/v. We interpret site‐specific variations with land subsidence or inflation detected by remote sensing. We also find a decade‐long postseismic response of two major earthquakes and bound the time scale of relaxation processes to a few years. Together, we see long‐term changes in seismic velocities showing a positive trend over two decades that we can interpret as long‐term lowering of the groundwater table.

Lithospheric S Wave Velocity Variations Beneath the Mackenzie Mountains and Northern Canadian Cordillera

AbstractThe Mackenzie Mountains (MMs) in the Yukon and Northwest Territories, Canada, are an enigmatic mountain range. They are currently uplifting (Leonard et al., 2008, https//doi.org/10.1029/2007JB005456), yet are about 700 km from the nearest plate boundary. Their arcuate shape is distinct and extends over 100 km eastward from the general trend of the Northern Canadian Cordillera. To better assess the cause and conditions of the current uplift, we processed ambient seismic noise data from a linear array of broadband seismographs crossing the mountains, along with other regional seismic stations, to estimate Rayleigh wave phase velocities between 6 and 40 s periods. From this, we estimated phase velocity dispersion and performed a tomographic inversion to estimate VS. Tomography reveals a low‐velocity structure that extends upward from the base of the ∼50–66 km thick lithosphere to the upper crust, and we hypothesize that inferred low density and low rigidity associated with the VS anomaly localizes the ongoing uplift and thrust‐dominated seismicity of the MMs. Additionally, we find relatively low crustal velocities that extend to the west of the MMs, suggesting that strain transfer from the Gulf of Alaska plate boundary plays a driving role as the crust translates to the northeast and buckles up against the craton consistent with the orogenic float hypothesis of Mazzotti and Hyndman (2002, https//doi.org/10.1130/0091-7613(2002)030〈0495:YCASTA〉2.0.CO;2). Finally, we observe lithospheric azimuthal anisotropy with an NW‐SE fast direction. This is nearly orthogonal to teleseismic shear wave splitting measurements in the central MMs, and suggests that asthenosphere flow and lithospheric strain are not aligned in this region.

SANS: Publicly Available Daily Multi‐Scale Seismic Ambient Noise Source Maps

AbstractSeismic ambient noise sources have received increased attention recently, creating new possibilities to study the Earth's subsurface and the atmosphere‐ocean‐solid Earth coupling. In efforts to locate such noise sources using nonlinear finite‐frequency inversions, methodological developments such as pre‐computed wavefields and spatially variable grids were necessary. These make inversions feasible for the secondary microseismic sources in a frequency range up to 0.2 Hz on a daily basis. By obtaining a starting model for the inversion using Matched Field Processing (MFP) we are able to further steer the inversion toward acceptable global noise source models and improve the final result. Analysis of 1 year of daily inversions shows the seasonal variations of the secondary microseisms and their dependence on the atmosphere‐ocean‐solid Earth coupling due to storm‐induced ocean waves. We present a web framework, seismic ambient noise sources (SANS, sans.ethz.ch), where daily regional‐ to global‐scale SANS maps for the secondary microseisms are made available to the public. This enables the implementation of time‐variable noise source distributions into full‐waveform ambient noise tomography and time‐dependent subsurface monitoring methods. Additionally, it can act as a reference for other studies that locate secondary microseismic sources on a larger scale.

Measuring the thickness and Young’s modulus of the ice pack with DAS, a test case on a frozen mountain lake

SUMMARY We explored the potential of fibre optics coupled with distributed acoustic sensing (DAS) to measure the thickness and Young’s modulus of an ice layer, using the properties of guided seismic waves. During two winter seasons (2020 and 2021), an optical fibre was deployed over one of the frozen Roberts Mountain lakes (at 2400 m a.s.l) near Grenoble (France) and we measured both the continuous ambient seismic noise as well as signals generated by active sources (hammer), with a DAS interrogator. Following a Bayesian scheme, we inverted the dispersion curves of longitudinal and flexural guided waves retrieved from the analysis of active shot gathers and obtained Young’s modulus E = 3.4 ± 0.1 GPa and ice thickness h = 47 ± 1 cm from the second-year data. The ice thickness was consistent with field measurements. Field observations of porous and/or fracture ice may explain the relatively low effective Young’s modulus (relative to pure ice), which may also be affected by a snow layer not included in the model. The drastic improvements in the inversion results between the two years are related to better coupling conditions (drone deployment before early freezing), more appropriate acquisition parameters (2 m gauge length), and the upper snow layers (less thick and less heterogeneous in the second year). Moreover, we were able to use the non-dispersive low-frequency noise associated with gravity waves to estimate the lake depth H = 5 m which is compatible with independent observations. The use of DAS to record guided seismic waves could then appear as a relevant tool for monitoring environments like floating ice shelves and sea ice.

Detection of clock errors in seismic records and estimation of time shifts for a seismic network

In the records of autonomous seismological observations occurrence of quartz watch clock drift often leads to incorrect time records. This paper presents a method for detecting such errors in a seismic station network based on the analysis of ambient seismic noise cross-correlation functions using Monte-Carlo Markov chain (MCMC) approach without using a reference signal. The proposed method was tested on the seismic data of a temporary seismic network installed on Paramushir Island in 2021-2022 for which time shifts were successfully estimated and corrections to the cross-correlation functions were made.

Constraints on fracture distribution in the Los Humeros geothermal field from beamforming of ambient seismic noise

Abstract. Faults and fractures are crucial parameters for geothermal systems as they provide secondary permeability allowing fluids to circulate and heat up in the subsurface. In this study, we use an ambient seismic noise technique referred to as three-component (3C) beamforming to detect and characterize faults and fractures at a geothermal field in Mexico. We perform 3C beamforming on ambient noise data collected at the Los Humeros Geothermal Field (LHGF) in Mexico. The LHGF is situated in a complicated geological area, part of a volcanic complex with an active tectonic fault system. Although the LHGF has been exploited for geothermal resources for over 3 decades, the field has yet to be explored at depths greater than 3 km. Consequently, it is currently unknown how deep faults and fractures permeate, and the LHGF has yet to be exploited to its full capacity. Three-component beamforming extracts the polarizations, azimuths and phase velocities of coherent waves as a function of frequency, providing a detailed characterization of the seismic wavefield. In this study, 3C beamforming of ambient seismic noise is used to determine surface wave velocities as a function of depth and propagation direction. Anisotropic velocities are assumed to relate to the presence of faults giving an indication of the maximum depth of permeability, a vital parameter for fluid circulation and heat flow throughout a geothermal field. Three-component beamforming was used to determine if the complex surface fracture system permeates deeper than is currently known. Our results show that anisotropy of seismic velocities does not decline significantly with depth, suggesting that faults and fractures, and hence permeability, persist below 3 km. Moreover, estimates of fast and slow directions, with respect to surface wave velocities, are used to determine the orientation of faults with depth. The north-east (NE) and north–north-west (NNW) orientation of the fast direction corresponds to the orientation of the Arroyo Grande and Maxtaloya–Los Humeros Fault swarms, respectively. NE and NNW orientations of anisotropy align with other major faults within the LHGF at depths permeating to 6 km.

3‐D S Wave Imaging via Robust Neural Network Interpolation of 2‐D Profiles From Wave‐Equation Dispersion Inversion of Seismic Ambient Noise

AbstractAmbient noise seismic data are widely used by geophysicists to explore subsurface properties at crustal and exploration scales. Two‐step dispersion inversion schema is the dominant method used to invert the surface wave data generated by the cross‐correlation of ambient noise signals. However, the two‐step methods have a 1‐D layered model assumption, which does not account for the complex wave propagation. To overcome this limitation, we employ a 2‐D wave‐equation dispersion (WD) inversion method which reconstructs the subsurface shear (S) velocity model in one step, and elastic wave‐equation modeling is used to simulate the subsurface wave propagation. In the WD method, the optimal S velocity model is obtained by minimizing the dispersion curve differences between the observed and predicted surface wave data, which makes WD method less prone to getting stuck to local minima. In our study, the observed Scholte waves are generated by cross‐correlating continuous ambient noise signals recorded by each ocean bottom node (OBN) in the 3‐D Gorgon OBN survey, Western Australia. For every two OBN lines, the WD method is used to retrieve the 2‐D S velocity structure beneath the first line. We then use a robust neural network (NN)‐based method to interpolate the inverted 2‐D velocity slices to a continuous 3‐D velocity model and also generate a corresponding uncertainty model. Moreover, we compared the predicted dispersion curves and waveforms to the observed data, and a robust waveform and dispersion match are observed across all of the Gorgon OBN lines.

Complementary Dense Datasets Acquired in a Low-to-Moderate Seismicity Area for Characterizing Site Effects: Application in the French Rhône Valley

Abstract Superficial geological layers can strongly modify the surface ground motion induced by an earthquake. These so-called site effects are highly variable from one site to another and still difficult to quantify for complex geological configurations. That is why site-specific studies can greatly contribute to improve the hazard prediction at a specific site. However, site-specific studies have historically been considered difficult to carry out in low-to-moderate seismicity regions. We present here seismological datasets acquired in the framework of the French–German dense array for seismic site effect estimation project in the heavily industrialized area surrounding the French Tricastin Nuclear Site (TNS). TNS is located above an ancient canyon dug by the Rhône River during the Messinian period. The strong lithological contrast between the sedimentary fill of the canyon and the substratum, as well as its expected confined geometry make this canyon a good candidate for generating site effects that are variable on short spatial scales. To investigate the impact of this geological structure on the seismic motion, we conducted complementary seismic campaigns in the area. The first main campaign consisted of deploying 400 nodes over a 10 × 10 km area for one month and aimed at recording the seismic ambient noise. A second seismic campaign involved the deployment of 49 broadband stations over the same area for more than eight months. This complementary campaign aimed at recording the seismicity (including local, regional, and teleseismic events). These different designs allowed us to target a variety of seismic data at different spatial and temporal scales. Beyond the interest for local operational seismic hazard applications, these datasets may be valuable for studying seismic wave propagation within complex kilometer-scale sedimentary structures. In this article, we present the deployment designs as well as initial analyses to provide information on the characteristics and the overall quality of the data acquired to future users.