We present a new version of the Statewide California Earthquake Center (SCEC) Community Fault Model (CFM 6.1) for southern California that describes more than 400 active faults that accommodate relative motions across the Pacific-North American plate boundary. CFM 6.1 is a substantially enhanced representation of the southern California fault system, with systematically updated and improved fault surfaces using detailed fault traces, precisely relocated earthquake and machine learning-enabled hypocenter catalogs (Ross, Trugman, et al., 2019), and new focal mechanism solutions (Lin et al., 2007; Hauksson et al., 2012 + updates; Yang et al., 2012), among other datasets. Several of the new fault representations, such as for the 2019 Ridgecrest, California (M 6.4 and 7.1) events, were developed using an objective, constraint-based interpolation method (Riesner et al., 2017). This resulted in reproducible fault representations that are more precise and often more segmented and interconnected than in previous model versions. The CFM 6.1 was peer reviewed and includes preferred representations for each fault system, along with alternative fault representations for which significant differences in subsurface structure have been proposed. Based on the earthquake-to-fault association method of Evans et al. (2020), the fault representations in CFM 6.1 show a 5.8% increased association with regional seismicity compared to CFM 5.2, with 89.7% of M 3 and larger events most likely associated with a CFM 6.1 fault. The faults also show a much higher degree of interconnectivity than in previous model versions, which will have implications for the assessment of potential earthquake ruptures involving multiple, distinct faults. The model is documented and distributed through a new website with a map and 3D views to facilitate broad usage with a wide range of applications in seismology, tectonic geodesy, computational modeling, and probabilistic and deterministic seismic hazard assessment.

Nearly a century of oil production in the Wilmington Oil Field, Los Angeles Basin, California, has modified the stress state, caused nearly 9 m of ground surface subsidence, and been associated with earthquakes that sheared wells. This offers a unique opportunity to elucidate the processes that govern these phenomena: Since the 1930s, approximately 2.5 billion barrels of oil have been produced, accompanied by water injection volumes roughly an order of magnitude larger. Combined with extensive structural and geophysical constraints, this history allows us to interrogate the long-term geomechanical impacts of reservoir operations. Here, we assess (i) how the initial stress state, typically uncertain in the shallow crust (<5 km depth), influences subsidence and uplift, and (ii) how production and injection operations affect fault stability. Our numerical model, calibrated with published measurements of reservoir pressures and surface displacements, incorporates a detailed representation of fault surfaces within and around the field, well-level production and injection schedules, and an elastoplastic constitutive framework. Model results show that the previously assumed stress regime in the field (reverse faulting) needs to be reassessedx2014the best match to the ground deformation data is achieved when the sedimentary section is initialized with low deviatoric stress (i.e., not critically stressed). This suggests significant variation in the stress state with depth, including a likely change in the stress regime. DCFF values suggest minor destabilization on reservoir faults and larger changes on sub-horizontal bedding planes; both could explain the faulting that led to sheared wells and seismicity between 1947 and 1961.

We present a cross-disciplinary approach to quantitatively evaluate the suitability of underground hydrogen storage (UHS) in hydrocarbon fields within the Los Angeles Basin, California. GIS mapping tools were applied to existing datasets from the California Geologic Energy Management Division, the U.S. Geoscience Information Network, and other open-sources to obtain quantitative measures of reservoir performance as well as infrastructure proximity and population density. We then applied the Analytic Hierarchy Process (AHP) in a three-tier hierarchy for this multi-criteria selection process. The AHP ranks each of the 67 subject fields in the basin against the study group according to performance in geologic, socioeconomic, and risk-driven criteria. Systematic pairwise comparisons across the complete set are used to derive weighted scores for UHS suitability, with weights informed from existing literature. The methodology results in comparative statements about relative reservoir suitability for UHS development and appears robust to uncertainties in weight setting. The method identifies the highest ranked fields as having large potential storage volumes, strong reservoir performance, and locations in more stable tectonic settings close to potential hydrogen production or transport infrastructure. In particular, El Segundo, Inglewood, Dominguez, Wilmington, and Playa Del Rey are identified as top performing candidates for UHS. The method, which is generally applicable and both computationally efficient and flexible, can be adjusted to consider alternative weighting of economic and environmental risk factors. This allows identifying top candidate fields for more specific reservoir engineering analysis of UHS suitability.

Very little of the seafloor is mapped and imaged to the extent needed to assess and monitor the changing ocean environment. The Monterey Bay Aquarium Research Institute develops systems to conduct seafloor surveys producing 1-cm-lateral resolution products over hundreds of square meter areas. The same sites can be revisited to understand physical, chemical, geological, and biological changes. Products from the surveys are published using traditional methods and data are submitted to national data archives such as the MGDS [1]. Because of the charismatic nature of some of our surveys a more engaging experience for the general public's access to data is desired. For this we envision using glTF, OGC 3D Tiles, and X3D to develop open-source workflows in our data processing system.

We investigate the influence of earthquake source characteristics and geological site parameters on fault scarp morphologies for thrust and reverse fault earthquakes using geomechanical models. A total of 3434 distinct element method (DEM) model experiments were performed to evaluate the impact of the sediment depth, density, homogeneous and heterogeneous sediment strengths, fault dip, and the thickness of unruptured sediment above the fault tip on the resultant coseismic ground surface deformation for a thrust or reverse fault earthquake. A machine learning model based on computer vision (CV) was applied to obtain measurements of ground surface deformation characteristics (scarp height, uplift, deformation zone width, and scarp dip) from a total of 346,834 DEM model stages taken every 0.05 m of slip. The DEM dataset exhibits a broad range of scarp behaviors, generating monoclinal, pressure ridge, and simple scarps—each of which can be modified by hanging wall collapse. The parameters that had the most influence on surface rupture patterns are fault displacement, fault dip, sediment depth, and sediment strength. The DEM results comprehensively describe the range of historic surface rupture observations in the Fault Displacement Hazards Initiative (FDHI) dataset with improved relationships obtained by incorporating additional information about the earthquake size, fault geometry, and surface deformation style. We suggest that this DEM dataset can be used to supplement field data and help forecast patterns of ground surface deformation in future earthquakes given specific anticipated source and site characteristics.

This study examines how fault dip and sediment strength influence along-strike variability in patterns of ground surface deformation during thrust and reverse fault earthquakes. Expanding on the 2D distinct element method (DEM) analysis by Chiama et al. (2023) and Chiama, Bednarz, et al. (2025), we develop 3D DEM models to investigate the influence of along-strike variability of geological site parameters on resultant morphologies of coseismic ruptures. The main fault scarp types-monoclinal, pressure ridge, and simple-are successfully reproduced in these 3D models, aligning with surface rupture characteristics previously identified in 2D modeling. Uniform fault dips and homogeneous sediment properties produce symmetrical (or cylindrical) fault scarps with uniform scarp morphologies, whereas local variations in fault dip, sediment strengths, and sediment thickness above the fault tip form a range of scarp geometries, deformation zone widths, and patterns of secondary fracturing. These 3D DEM models reproduce patterns of surface fault ruptures observed in natural settings. Overall, the 3D models support the relationships of ground surface deformation characteristics (scarp class, width, and height) with source and sediment properties established in the 2D DEM results of Chiama, Bednarz, et al. (2025). In addition, they provide new insights into how fault dip and sediment strength govern along-strike transitions in fault scarp morphology. In combination, the results of the 2D and 3D DEM model results can be used to infer patterns of surface ruptures based on local geological site conditions and fault characteristics.

SUMMARY A theory for modelling the evolution of elastic moduli of grain packs under increasing pressure is combined with a method that accounts for the presence of fine-grained particles to develop a new conceptual framework for computing the seismic velocities of compacting sediments. The resulting formulation is then used to construct a seismic velocity model for California’s Central Valley. Specifically, a set of 44 sonic logs from the San Joaquin Valley are combined with soil textural data to derive the 3-D velocity variations in the province. An iterative quasi-Newton minimization algorithm that allows for bounded variables provided estimates of the nine free parameters in the model. The estimates low- and high-pressure exponents that resulted from the fit to the sonic log velocities are close to 1/2 and 1/3, respectively, values that are observed in laboratory experiments. Our results imply that the grain surfaces are sufficiently rough that there is little or no slip between grains. Thus, the deformation may be modelled using a strain energy function or free energy potential. The estimated Central Valley velocity model contains a 27 per cent increase in velocity from the surface to a depth of 700 m. Lateral variations of around 4 per cent occur within the layers of the model, a consequence of the textural heterogeneity within the subsurface.

Differences/Disorders of sex development (DSDs) are conditions in which the development of chromosomal, gonadal, and anatomical sexes is atypical. DSDs are relatively rare, but their incidence is becoming alarmingly common in sub-Saharan Africa (SSA). Their etiologies and mechanisms are poorly understood. Therefore, we have investigated cytogenetic profiles, including telomere dysfunction, in a retrospective cohort of Senegalese DSD patients. Materials and methods: Peripheral blood lymphocytes were sampled from 35 DSD patients (mean age: 3.3 years; range 0–18 years) admitted to two hospital centers in Dakar. Peripheral blood lymphocytes from 150 healthy donors were used as a control. Conventional cytogenetics, telomere, and centromere staining followed by multiplex FISH, as well as FISH with SRY-specific probes, were employed. Results: Cytogenetic analysis identified 19 male and 13 female patients with apparently normal karyotypes, two patients with Turner syndrome, and one patient with Klinefelter syndrome. Additional structural chromosome aberrations were detected in 22% of the patients (8/35). Telomere analysis revealed a reduction in mean telomere lengths of DSD patients compared to those of healthy donors of similar age. This reduction in telomere length was associated with an increased rate of telomere aberrations (telomere loss and the formation of telomere doublets) and the presence of additional chromosomal aberrations. Conclusions: To the best of our knowledge, this study is the first to demonstrate a correlation between telomere dysfunction and DSDs. Further studies may reveal the link between telomere dysfunction and possible mechanisms involved in the disease itself, such as DNA repair deficiency or specific gene mutations. The present study demonstrates the relevance of implementing telomere analysis in prenatal tests as well as in diagnosed genetic DSD disorders.

We describe our concept and implementation outline of bridging two popular but disconnected geospatial ecosystems, Web3D Consortium's X3D and OGC's 3D Tiles with the goal of achieving synergies to both while improving workflows. There are potentially many benefits of integrating these two complementary geospatial open standards such as leveraging OGC toolchains for X3D, providing access to rich X3D interactivity for OGC 3D Tiles or building the foundations for streaming of massive 3D geospatial datasets within X3D. We propose to test this idea by implementing a large subset of OGC 3D Tiles 1.1 functionality for X3DOM, an open source X3D browser, and to show how existing and well tested XD features could aid such an implementation. As a result, we sketch a strategy to include OGC 3D Tilesets declaratively in a fully interactive X3D world, with accurate geospatial registration and integration with the X3D Geospatial component.

This paper explores the integration of eXtended Reality (XR) content within X3DOM, a popular framework for displaying 3D content in web browsers. The importance of Web3D and the prevalent use of the X3D file format are discussed. With the deprecation of WebVR and the adoption of WebXR in web browsers, X3DOM has emerged as one of the pioneering adaptors of WebXR APIs. This paper highlights the current capabilities of X3DOM, which enable users to explore 3D scenes on regular screens and seamlessly transition into Virtual Reality (VR) mode. It showcases the use of controllers for navigation and the execution of custom functions within the X3D scenes. Additionally, the paper presents a series of developed 3D scenes that demonstrate the effectiveness of X3DOM in rendering VR content, ranging from indoor to outdoor environments, utilizing X3D nodes to display images and videos to create immersive photospheres and rich interactive scenes.

We seek to improve our understanding of the physical processes that control the style, distribution, and intensity of ground surface ruptures on thrust and reverse faults during large earthquakes. Our study combines insights from coseismic ground surface ruptures in historic earthquakes and patterns of deformation in analog sandbox fault experiments to inform the development of a suite of geomechanical models based on the distinct element method (DEM). We explore how model parameters related to fault geometry and sediment properties control ground deformation characteristics such as scarp height, width, dip, and patterns of secondary folding and fracturing. DEM is well suited to this investigation because it can effectively model the geologic processes of faulting at depth in cohesive rocks, as well as the granular mechanics of soil and sediment deformation in the shallow subsurface. Our results show that localized fault scarps are most prominent in cases with strong sediment on steeply dipping faults, whereas broader deformation is prominent in weaker sediment on shallowly dipping faults. Based on insights from 45 experiments, the key parameters that influence scarp morphology include the amount of accumulated slip on a fault, the fault dip, and the sediment strength. We propose a fault scarp classification system that describes the general patterns of surface deformation observed in natural settings and reproduced in our models, including monoclinal, pressure ridge, and simple scarps. Each fault scarp type is often modified by hanging-wall collapse. These results can help to guide both deterministic and probabilistic assessment in fault displacement hazard analysis.

In the event of a radiological or nuclear accident, or when physical dosimetry is not available, the scoring of radiation-induced chromosomal aberrations in lymphocytes constitutes an essential tool for the estimation of the absorbed dose of the exposed individual and for effective triage. Cytogenetic biodosimetry employs different cytogenetic assays including the scoring of dicentrics, micronuclei, and translocations as well as analyses of induced premature chromosome condensation to define the frequency of chromosome aberrations. However, inherent challenges using these techniques include the considerable time span from sampling to result, the sensitivity and specificity of the various techniques, and the requirement of highly skilled personnel. Thus, techniques that obviate these challenges are needed. The introduction of telomere and centromere (TC) staining have successfully met these challenges and, in addition, greatly improved the efficiency of cytogenetic biodosimetry through the development of automated approaches, thus reducing the need for specialized personnel. Here, we review the role of the various cytogenetic dosimeters and their recent improvements in the management of populations exposed to genotoxic agents such as ionizing radiation. Finally, we discuss the emerging potentials to exploit these techniques in a wider spectrum of medical and biological applications, e.g., in cancer biology to identify prognostic biomarkers for the optimal triage and treatment of patients.

Inelastic processes from earthquakes contribute to the formation of fault damage zones that constitute a permanent sink of strain energy, modify the elastic properties of the shallow crust and amplify near-field ground shaking. Constraints on the extent of inelastic deformation differ depending on the dataset and methodology used. Here we combine fracture, strain and aftershock maps from the 2019 Ridgecrest earthquakes to reconcile the properties of damage zones across different spatial scales and resolutions. The decay of inelastic deformation with distance from the fault is well described by an inverse power law, extends beyond 20 km from the faults and is insensitive to lithology and slip magnitude. The damage decay is continuous without breaks in scaling, suggesting that a single mechanism dominates yielding. On the basis of our fracture density distribution, we predict an average reduction in shear rigidity of about 20% in bedrock and 40% in alluvium immediately adjacent to the fault, declining to less than 1% at 100 m. Our observations reveal how macroscopic fracturing generates intense near-fault damage and that widespread damage accrues regionally over multiple earthquake cycles.

ABSTRACT The Palos Verdes fault zone (PVFZ) extends across the southwestern Los Angeles basin and Inner Continental Borderland, California, and is considered capable of generating large (Mw>7), damaging earthquakes with short recurrence intervals. The 110 km long fault zone is composed of vertical and moderately dipping segments that accommodate oblique, right-lateral reverse displacement. Onshore, there is a counterclockwise reorientation in the PVFZ’s strike, which produces a major restraining bend that generates the Palos Verdes Peninsula. Here, we use well and seismic reflection data to develop kinematic models that show folding of the PVFZ by the Wilmington blind thrust led to formation of the restraining bend. North of the peninsula in Santa Monica Bay, debate persists over the extent, geometry, and activity of the PVFZ. Here, we analyze a dense grid of high-resolution seismic reflection data and present a new mapping of the Santa Monica Bay segment of the PVFZ, including multiple active splays (e.g., Redondo Canyon fault zone) that occur within a broad damage zone at the northern termination of the fault system. Based on these insights and prior studies, we develop a new, comprehensive 3D model of the PVFZ including its Santa Monica Bay, San Pedro Bay, and Lasuen Knoll segments. The sizes of these segments indicate that PVFZ is capable of larger events than previously reported—Mw 7.1–7.4 for single-segment ruptures and Mw 7.4–7.8 for multisegment ruptures. Based on a reported slip rate of 1.1–5.9 mm/yr, average recurrence intervals for these single- and multisegment rupture scenarios are 580–610 and 760–1170 yr, respectively.

Telomeres play a major role in maintaining genome stability and integrity. Putative involvement of telomere dysfunction in the formation of various types of chromosomal aberrations is an area of active research. Here, we report a case of a six-month-old boy with a chromosomal gain encompassing the 11q22.3q25 region identified by SNP array analysis. The size of the duplication is 26.7 Mb and contains 170 genes (OMIM). The duplication results in partial trisomy of the region in question with clinical consequences, including bilateral renal dysplasia, delayed development, and a heart defect. Moreover, the karyotype determined by R-banding and chromosome painting as well as by hybridization with specific sub-telomere probes revealed the presence of an unbalanced t(9;11)(p24;q22.3) translocation with a unique breakpoint involving the sub-telomere region of the short arm of chromosome 9. The karyotypes of the parents were normal. Telomere integrity in circulating lymphocytes from the child and from his parents was assessed using an automated high-throughput method based on fluorescence in situ hybridization (FISH) with telomere- and centromere-specific PNA probes followed by M-FISH multicolor karyotyping. Very short telomeres, as well as an increased frequency of telomere loss and formation of telomere doublets, were detected in the child’s cells. Interestingly, similar telomere profiles were found in the circulating lymphocytes of the father. Moreover, an assessment of clonal telomere aberrations identified chromosomes 9 and 11 with particularly high frequencies of such aberrations. These findings strongly suggest that telomere dysfunction plays a central role in the formation of this specific unbalanced chromosome rearrangement via chromosome end-to-end fusion and breakage–fusion–bridge cycles.

ABSTRACTThe Mid-Channel fault is an active blind thrust overlain by a south-vergent anticline in the Santa Barbara channel of southern California. We use high-quality industry seismic reflection data to characterize the 3D geometry of the Mid-Channel fault, and define its lateral extent and interactions with other structures in the region. We use a detailed chronostratigraphic sequence of nine Pleistocene horizons ranging in age from 120 ka to 1.05 Ma to interpret the geometry and deformational history of the Mid-Channel anticline and blind thrust. These precisely dated horizons provide unique insights on the Pleistocene activity of the Mid-Channel fault because of the nearly complete preservation of sediment on the backlimb of the fold. Using a new method of relating structural relief of these horizons to slip on the underlying Mid-Channel fault, we calculate the faults late Pleistocene slip rate. Results indicate that the structure became active between 790 and 710 ka in the eastern part of the Channel and subsequently propagated west along strike. In the east, where the overlying anticline preserves a complete section of syntectonic growth strata, the Mid-Channel fault has a dip-slip rate of 1.8 mm/yr with a range of 1.6–2.1 mm/yr. Based on a map of total displacement, we infer that the maximum dip-slip rate on the Mid-Channel fault along strike is 2.1 ± 0.2 mm/yr, suggesting that it may accommodate about one-third of the observed geodetic contraction across the basin. We explore alternative ways that the fault may extend to depth and interact with surrounding structures, and consider the seismic hazard implications of these scenarios, including estimates of potential earthquake rupture areas, magnitudes, and average recurrence intervals.

There is growing concern about seismicity triggered by human activities, whereby small increases in stress bring tectonically loaded faults to failure. Examples of such activities include mining, impoundment of water, stimulation of geothermal fields, extraction of hydrocarbons and water, and the injection of water, CO 2 and methane into subsurface reservoirs 1 . In the absence of sufficient information to understand and control the processes that trigger earthquakes, authorities have set up empirical regulatory monitoring-based frameworks with varying degrees of success 2 , 3 . Field experiments in the early 1970s at the Rangely, Colorado (USA) oil field 4 suggested that seismicity might be turned on or off by cycling subsurface fluid pressure above or below a threshold. Here we report the development, testing and implementation of a multidisciplinary methodology for managing triggered seismicity using comprehensive and detailed information about the subsurface to calibrate geomechanical and earthquake source physics models. We then validate these models by comparing their predictions to subsequent observations made after calibration. We use our approach in the Val d’Agri oil field in seismically active southern Italy, demonstrating the successful management of triggered seismicity using a process-based method applied to a producing hydrocarbon field. Applying our approach elsewhere could help to manage and mitigate triggered seismicity.

ABSTRACT The injection experiment conducted at the Rangely oil field, Colorado, was a pioneering study that showed qualitatively the correlation between reservoir pressure increases and earthquake occurrence. Here, we revisit this field experiment using a mechanistic approach to investigate why and how the earthquakes occurred. Using data collected from decades of field operations, we build a geological model for the Rangely oil field, perform reservoir simulation to history match pore-pressure variations during the experiment, and perform geomechanical simulations to obtain stresses at the main fault, where the earthquakes were sourced. As a viable model, we hypothesize that pressure diffusion occurred through a system of highly permeable fractures, adjacent to the main fault in the field, connecting the injection wells to the area outside of the injection interval where intense seismic activity occurred. We also find that the main fault in the field is characterized by a friction coefficient μ ≈ 0.7—a value that is in good agreement with the classical laboratory estimates conducted by Byerlee for a variety of rock types. Finally, our modeling results suggest that earthquakes outside of the injection interval were released tectonic stresses and thus should be classified as triggered, whereas earthquakes inside the injection interval were driven mostly by anthropogenic pore-pressure changes and thus should be classified as induced.

Dicentric chromosomes are a relevant marker of chromosomal instability. Their appearance is associated with telomere dysfunction, leading to cancer progression and a poor clinical outcome. Here, we present Telomere and Centromere staining followed by M-FISH (TC+M-FISH) for improved detection of telomere dysfunction and the identification of dicentric chromosomes in cancer patients and various genetic syndromes. Significant telomere length shortening and significantly higher frequencies of telomere loss and deletion were found in the peripheral lymphocytes of patients with cancer and genetic syndromes relative to similar age-matched healthy donors. We assessed our technique against conventional cytogenetics for the detection of dicentric chromosomes by subjecting metaphase preparations to both approaches. We identified dicentric chromosomes in 28/50 cancer patients and 21/44 genetic syndrome patients using our approach, but only 7/50 and 12/44, respectively, using standard cytogenetics. We ascribe this discrepancy to the identification of the unique configuration of dicentric chromosomes. We observed significantly higher frequencies of telomere loss and deletion in patients with dicentric chromosomes (p < 10−4). TC+M-FISH analysis is superior to classical cytogenetics for the detection of chromosomal instability. Our approach is a relatively simple but useful tool for documenting telomere dysfunction and chromosomal instability with the potential to become a standard additional diagnostic tool in medical genetics and the clinic.

Channel and fan systems in deep-water continental slopes respond to active deformation creating patterns within growth strata that record the history of deformation. These patterns provide important constraints on the timing and kinematics of structural deformation. We show how the location and orientation of depositional systems are affected by the emergence and growth of fault-related folds. We develop two end-member three-dimensional kinematic models to describe the reaction of channels to growing structures. In the first model, structures grow through lateral propagation, causing channels to migrate laterally outward through time. In the second model, structures grow with fixed lateral limits, and channels maintain relatively fixed positions through time. We compare our models with structures in the outer fold-thrust belt in the Niger Delta. The initiation of structural growth is recorded by a dramatic change in channel architecture with a reduction in sinuosity followed by deflection around the lateral edges of folds. Subsequently, in some examples, channels maintain relatively fixed positions through time, reflective of fold growth with fixed lateral limits, whereas other examples show channels that migrate laterally outward through time, reflecting fold growth by lateral propagation. We corroborate our interpretations by comparing our analysis of channel distribution to isopach and structure contour maps. Results indicate that structures in close proximity can grow through different mechanisms or a combination of mechanisms over different stages in their development. The resolved patterns of channel and fan systems provide insight into the complex distribution of reservoir facies, which has important implications for reservoir characterization.