The episodic transient fault slips called slow slip events (SSEs) have been observed in many subduction zones. These slips often occur in regions adjacent to the seismogenic zone during the interseismic period, making monitoring SSEs significant for understanding large earthquakes. Various fault slip behaviors, including SSEs and earthquakes, can be explained by the spatial heterogeneity of frictional

Satellite laser ranging (SLR) measurements play a key role in determining global geodetic parameters, such as station coordinates, geocenter motion, low-degree Earth's gravity field parameters, and Earth rotation parameters. Observations to two LAser GEOdynamics Satellites (LAGEOS) and two Etalon satellites provide operational standard products and contribute to the realization of the scale and the

The Hawaiian Ridge has long been a focus site for studying lithospheric flexure due to intraplate volcano loading, but crucial load and flexure details remain unclear. We address this problem using wide-angle seismic refraction and reflection data acquired along a ∼535-km-long profile that intersects the ridge between the islands of Maui and Hawai'i and crosses 80–95 Myr-old lithosphere. A tomographic

Fluid-induced earthquakes adversely affect industrial operations like hydraulic fracturing (e.g., 4.6 Mw in Alberta, Canada) and enhanced geothermal systems (e.g., 5.5 Mw in Pohang, South Korea). Identifying all underlying physical processes contributing to fluid-induced seismicity presents an open challenge. Recent work reports signatures of event-event triggering or aftershocks—common for tectonic

Geometric heterogeneities in tight reservoir rocks saturated with a fluid mixture may exhibit different scale distribution characteristics. Conventional models of rock physics based on poroelasticity, which usually consider single-scale pore structure and fluid patches, are inadequate for describing elastic wave responses. A major challenge is to establish the relationship between the wave response

A combination of receiver function (RF) analysis and shear wave splitting can reveal the anisotropic properties of the Earth's velocity structure. The RF profile exhibits harmonic patterns partially generated from the discontinuities of anisotropic media near the receiver. The anisotropic properties are determined using splitting parameters, which include the fast polarization direction (FPD) and split

We propose a new model for the crust and upper mantle in Iran by joint inversion of gravity and magnetic fields, constrained with a seismic tomography model. We then calculate shear modulus from the Vs velocities and densities. The crust and mantle tomography model is first converted to a density cube through empirical and petrological velocity-density relations. The starting susceptibility is assigned

Tsunamis can have devastating consequences for coastal communities. Yet hazards from future tsunamis are difficult to quantify due to their rarity in the instrumental record. Statistical earthquake catalogs have previously been used to quantify tsunami hazards. For the first time, we use a physics-based synthetic earthquake catalog to assess probabilistic tsunami hazard in a local region. We analyze

Magma supply likely exerts primary control on seafloor morphology of oceanic crust, but most studies have related morphology to spreading rate. Here we examine global patterns of morphology on mid-ocean ridge (MOR) flanks in relation to magma supply derived from residual mantle Bouguer gravity anomaly (proxy for relative crustal thickness) and spreading rate. We use multibeam bathymetry to characterize

No abstract is available for this article.

Monitoring groundwater levels in aquifers is crucial for water resources management on a global scale. In Greece, water stress is particularly high due to the expansion of agricultural land, urbanization and tourism, leading to aquifer over-exploitation. In this study, we investigate the possibility of monitoring groundwater reservoirs from seismic velocity changes (δv/v) measured using noise autocorrelations

Along the strike of subduction zones, tectonic tremor episodicity is segmented on a geologic scale. Here, we study how this segmentation reflects large-scale variations of the structure and conditions of the fault interface where tremor is generated. We try to understand which properties of the hydraulic system of the fault allow elementary tremor sources to synchronize, leading to the emergence of

Hydroclimate is an important factor controlling landscape evolution. But establishing the impact of hydroclimate is complicated by the influences of other processes and is especially hard to prove for those in deep time from geological record. During the late Permian, voluminous basaltic sediments were derived from the erosion of the Emeishan large igneous province in western South China. They provide

Over the past decade, the seismicity rate in the state of Oklahoma has increased significantly, which has been linked to industrial operations, such as saltwater injection and hydraulic fracturing. Taking advantage of induced earthquakes and recently deployed seismometers, we construct a 3-D radially anisotropic seismic velocity model for the crust of Oklahoma by using full waveform inversion. To mitigate

The contribution of water to the formation of large igneous provinces (LIPs) remains controversial. We report the first measurement of water content and hydrogen isotope ratios in olivine-hosted melt inclusions from the Dali picrites, which belong to the Emeishan LIP (ELIP). The inclusions have a wide range of H2O content (0.01–1.73 wt %) and H isotope ratios (δD = 87 ± 11‰ to −267 ± 14‰). The lowest

Talc is widely distributed in metamorphic and hydrothermally altered rocks, and its velocity is useful for constraining the velocity of mantle wedge. In this study, we used ultrasonic interferometry to study the elastic properties of talc polycrystalline samples at high pressure (up to 5.6 GPa). VP increases monotonically with increasing pressure, and VS increases with pressure up to ∼3.2 GPa, but

Mantle oxidation plays an essential role in volatile cycling between Earth’s interior and exterior. However, the conceivable oxidizer remains enigmatic and needs to be explored by geochemical tools. Here, we examine the potential of recycled carbonates in inducing redox changes of the deep mantle through combined isotopic studies of Mg (δ26Mg), Zn (δ66Zn), Fe (δ56Fe), and Cu (δ65Cu) on a suite of intraplate

Fabrics, also known as textures or crystallographic preferred orientations, reveal information about the deformation history of the flow of polycrystalline materials, including glacial ice, olivine in the mantle, and feldspar and quartz in the crust. Ice fabrics can have an order-of-magnitude effect on the ease of flow in ice sheets. However, due to the choice of ice core drill site locations, the

Many rocks exhibit a structural composition, which leads to an anisotropic behavior of different properties. A proper understanding of the directional dependency of these properties is required to analyze and predict the failure behavior of the rock mass upon stress changes during many geo-engineering applications. This study investigates the selected host rock for nuclear waste disposal in Switzerland

Understanding and determining the composition and evolution of the upper mantle is valuable to unravel Earth's evolutionary geodynamics. The compositions of oceanic basalts are inevitably biased by the preferential melting of fusible mantle components and the pooling of melts from multiple sources. Here we present whole rock and mineral chemistry as well as Re-Os isotopic systematics of the Table Mountain

Subduction-induced metasomatism may increase heterogeneity in the subcontinental lithospheric mantle (SCLM) over time. Syenite and its relevant varieties are typically derived from the most metasomatized portions of the SCLM and thus provide a key to decipher its heterogeneity. The only circum-cratonic syenite province in the world, the Late Triassic belt around North China craton, is unique and offers

The Southern Ocean (SO) plays a fundamental role in global climate due to the presence of the intense eastward-flowing Antarctic Circumpolar Current (ACC), one of the most important ocean current systems. The configuration of the frontal systems of the ACC is controlled by the orbital- and millennial-scale variations of the Southern Hemisphere westerly winds (SHWW) and the SO upwelling. However, the

Arc-backarc systems are inherently shaped by subduction, representing an essential window into processes acting in the Earth's interior such as the recycling of subducted slabs. Furthermore, they are setting where new crust is formed and are believed to be sites where juvenile continental crust emerges. We present a seismic refraction and wide-angle velocity model across the Izu arc-backarc system

The additional work of ploughing makes seamounts more resistant to subduction and more strongly coupled than smoother areas. Nevertheless, the idea that subducted seamounts are weakly coupled and slip aseismically has become dominant in the last decade. This idea is primarily based on the claim that a seamount being subducted in the southern Japan Trench behaves this way. The key element in this assertion

The Makran subduction zone is unique in its wide onshore thick accretionary prism, and volcanic arc not parallel to the E–W trend of the Makran accretionary prism. To investigate the internal structure of the accretionary prism, the crustal nature of Jaz Murian Depression, and the trend of the subducting plate hinge, we have calculated a 3D shear-wave velocity model for a region around the border between

Plate tectonics is a tectonic style thought to be the hallmark of habitable planets, and yet the inherent complexities of plate tectonic convection have clouded the establishment of simple scaling laws with which to model convective behavior and thermal evolution. We have recently developed a scaling approach for mixed heated convection, based upon several simple physical principles. Here, we generalize

To better understand how normal stress heterogeneity affects earthquake rupture, we conducted laboratory experiments on a 760 mm poly (methyl-mathacrylate) PMMA sample with a 25 mm “bump” of locally higher normal stress (∆σbt). We systematically varied the sample-average normal stress ( σ n ‾ $\overline{{\sigma }_{n}}$ ) and bump prominence ( ∆ σ bt / σ n ‾ ${{\increment}\sigma }_{\text{bt}}/\overline{{\sigma

Oceanic detachment faulting, a major mode of seafloor accretion at slow and ultraslow spreading ridges, is thought to occur during magma-poor phases and be abandoned when magmatism increases. In this framework, detachment faulting is the result of temporal variations in magma flux, which is inconsistent with recent geophysical observations at the Longqi segment on the Southwest Indian Ridge (49°42′E)

It remains unresolved whether extensive granitoids can originate from ultrahigh-temperature crustal anatexis beyond the stability of fusible hydrous minerals and, if any, how they are generated and characterized. Here we investigate near-anhydrous garnet granitoids in the Jining Complex, North China, using bulk-rock and mineral analyses combined with phase equilibria modeling. The Jining garnet granitoids

The presence of eclogite marks high-pressure metamorphism and deep, cold burial of crust, and is therefore a widely accepted indicator for the onset of modern-style plate tectonics. However, eclogite is rarely preserved in many heavily granulite-overprinted orogens, which are particularly common across ancient metamorphic terranes (i.e., Archean and Paleoproterozoic terranes). Here, we show that eclogite

Graphite is considered as a material that promotes fault weakening and electrical conductivity (σ) enhancement at fault zones. We studied how shear deformation may affect the evolution of friction and electrical conductivity of synthetic quartz (Qz)-graphite (Gr) mixtures and, more importantly, whether the σ of the mixtures present visible changes at the beginning of the simulated fault slip. Long-displacement

Physics-based earthquake simulators have been developed to overcome the relatively short duration and incompleteness of historical earthquake and paleoseismic records, respectively. These simulators have the potential to be a useful addition to seismic hazard assessment as they produce millions of synthetic earthquakes over thousands to millions of years using predefined fault geometries and slip rates

Stratified thin layers often present a prominent mechanical contrast with regard to the embedding background and, hence, are important targets for seismic reflection studies. An efficient way to study the reflectivity response of these thin layers is to employ their homogenized viscoelastic equivalents. We aim to homogenize a simple, yet realistic, thin-layer model, which is composed of a finite non-periodic

Tectonic activity, geothermal fluids, and microseismic events (MSEs) tend to occur in similar locations as a result of spatiotemporal changes in the subsurface stress state. To quantify this association, we analyze data from a dense seismic array deployed at the San Emidio geothermal field, Nevada for 1 week in December 2016 to coincide with a 19.45-hr shutdown of all injection and production pumping

Imaging the structure of major fault zones is essential for our understanding of crustal deformations and their implications on seismic hazards. Investigating such complex regions presents several issues, including the variation of seismic velocity due to the diversity of geological units and the cumulative damage caused by earthquakes. Conventional migration techniques are in general strongly sensitive

Seismicity in the New Madrid seismic zone and the rest of stable North America remains controversial. Some workers view present-day earthquakes there as long-lived aftershocks; others view them as background seismicity concentrated in lithospheric weak zones. Separating long-lived aftershocks from background seismicity, however, is challenging. Here, we used the nearest-neighbor (NN) method to identify

The 2015 Mw 7.8 Gorkha (Nepal) earthquake induced prolonged postseismic deformation extending northward beyond the Yarlung Zangbo Suture, which provides unique opportunities to better understand the lithospheric rheology in Himalaya and southern Tibet. Here, we used the first 5-year Global Positioning System observations to study the main postseismic processes following this event, including viscoelastic

Recent research has suggested that East Asia has experienced a prevailing monsoon climate since the Eocene. However, there is little knowledge about the development of the East Asian monsoon system before the Miocene, particularly in southern China, due to a lack of well-dated continuous sediment records. Here, we present new magnetic proxy records from International Ocean Discovery Program Site U1501

Infrasound—acoustic waves in the atmosphere below 20 Hz—is a useful monitoring tool. Topography and atmospheric structure strongly control infrasound propagation, and at common source–receiver distances neither of these effects can be ignored when quantitative source constraints are sought. Detailed spatial measurements of the infrasound wavefield would inform propagation models and improve source

In analyzing terrestrial water storage (TWS) data observed by Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On satellites, quantifying uncertainties proves challenging due to the scarcity of sufficient independent observations of mass changes at scales commensurate with these missions. Moreover, owing to the diverse geophysical background models and processing techniques utilized

We introduce the Ensemble Earthquake Early Warning System (E3WS), a set of Machine Learning (ML) algorithms designed to detect, locate, and estimate the magnitude of an earthquake starting from 3 s of P-waves recorded by a single station. The system is made of six Ensemble ML algorithms trained on attributes computed from ground acceleration time series in the temporal, spectral, and cepstral domains

Serpentinite dehydration is important for subduction zone dynamics and water cycling. Field observations suggest that en échelon olivine veins in serpentinite mylonites formed by dehydration during simultaneous shearing of antigorite serpentinite. Here, we test the hypothesis of shear-driven formation of olivine dehydration veins with a novel two-dimensional hydro-mechanical-chemical numerical model

We model Coulomb stress transfer (CST) due to 30 strong earthquakes occurring on normal faults since 1509 CE in Calabria, Italy, including the influence of interseismic loading, and compare the results to existing studies of stress interaction from the Central and Southern Apennines, Italy. The three normal fault systems have different geometries and long-term slip-rates. We investigate the extent

Shear rupture and fault slip in crystalline rocks like granite produce large dilation, impacting the spatiotemporal evolution of fluid pressure in the crust during the seismic cycle. To explore how fluid pressure variations are coupled to rock deformation and fault slip, we conducted laboratory experiments under upper crustal conditions while monitoring acoustic emissions and in situ fluid pressure

We measured poroelastic properties of cracked granite under triaxial conditions, at elevated confining pressure and a range of differential stresses. Skempton's coefficients and undrained Young's modulus and Poisson's ratio were determined directly by recording in situ fluid pressure during rapid cycles of axial and radial stress. Drained properties were measured both statically and dynamically at

The Southern San Andreas Fault (SSAF) in California is one of the most thoroughly studied faults in the world, but its configuration at seismogenic depths remains enigmatic in the Coachella Valley. We use a combination of space geodetic and seismic observations to demonstrate that the relatively straight southernmost section of the SSAF, between Thousand Palms and Bombay Beach, is dipping to the northeast

Triggering intrusions of phreatic eruptions are often observed as seismic and ground deformation signals on a time scale of minutes. The current understanding of hydrothermal intrusions still needs improvement to obtain insight into the eruption scale from the observables. We examine local geophysical data from the precursory hydrothermal intrusion of the 2018 phreatic eruption of Kusatsu-Shirane volcano

The NW Himalayan “seismic gap” lies between the 1905 and 2005 earthquake rupture zones and straddles the meisoseismal zone of the 1555-Kashmir earthquake. Sufficient elastic strain has now accumulated across this region to drive a mega-thrust earthquake. We model the crustal structure and geometry of the Main Himalayan Thrust (MHT) using Jammu and Kashmir Seismological NETwork data. P-wave receiver-function

We presented two high-resolution, three-dimensional (3D) global P- and joint S-wave velocity models of the whole mantle with a particular focus on the North Pacific realm using our new global tomographic inversion method. The 3D ray tracing based on data-adaptive block parameterization was implemented to calculate ∼17 million body-wave absolute travel times and ray paths of multiple classes (e.g.,

Geysers fascinate scientists and visitors for several centuries. However, many driving mechanisms such as heat transfer in the conduit and in the subsurface remain poorly understood. We document for the first time transient temperature variations inside the active Strokkur's and nearby quasi-dormant Great Geysir's conduits, Iceland. While recording temperature inside the conduit, we visually monitored

No abstract is available for this article.

We experimentally investigated the phase relations of a primary basaltic glass erupted on the 10–15°E ultraslow spreading (∼0.4 cm/yr) oblique amagmatic segment of the Southwest Indian Ridge (SWIR). Piston-cylinder experiments were conducted at 9–13 kbar and 1270–1310°C, in accordance with the predicted pressure and temperature (9.5 ± 0.8 kbar and 1290 ± 12°C) of saturation with a mantle lherzolite

Slow-earthquake signals are generally smaller than or comparable to noise levels at almost all seismological frequencies. Comprehensive detection of these events requires continuous waveforms from many stations, but such data are not always available, even in regions with high slow-earthquake activity. We therefore need a simple and stable detection method that is also applicable to regions with sparse

Knowledge of earthquake source faults is crucial for the calculation of robust Coulomb stress models. However, source faults are often poorly constrained, especially for pre-instrumental events, and these historical earthquakes are commonly studied with little or no consideration of other nearby events. We introduce an approach using Coulomb Stress Transfer (CST) modeling to investigate historical

The study of slow slip events is essential to elucidating the slip mechanisms and frictional properties of plate interfaces. We imaged the aseismic slip at the plate interface between the subducting Philippine Sea Plate and overriding Amur Plate beneath Shikoku Island, Japan, by applying a network inversion filter to the position time series obtained from Global Navigation Satellite System data spanning

Large earthquakes in the vicinity of Antarctica have the potential to cause postseismic viscoelastic deformation affecting measurements of displacement that are used to constrain models of glacial isostatic adjustment (GIA). In November 2013, a Mw 7.7 strike-slip earthquake occurred in the Scotia Sea, 650 km from the Antarctic Peninsula. GPS time series from the northern Peninsula show a change in

SiO2 is an important modally abundant component of terrestrial planets, while there are few studies that quantitatively determine the properties of silica under simultaneously high-temperature and high-pressure conditions. In this study, thermal properties of stishovite, CaCl2-type SiO2 and seifertite have been obtained by using extensive first-principles simulations. The quasi-harmonic approximation

The lithospheric architecture of the South China Block (SCB) is crucial to understanding the formation and evolution of this distinctive and highly reworked continental lithosphere with over 3 billion years of tectonic history. However, due to a lack of high-resolution geophysical datasets, a detailed picture of the SCB lithosphere is absent, and fundamental questions regarding its formation, assembly

In the Western Alps, oceanic lithosphere fragments recovered from subduction are exposed continuously across the Liguro-Piemont domain. In this nappe-stack, the Schistes Lustrés metasediments are volumetrically dominant and contain large amounts of high-pressure lawsonite- and Fe-Mg carpholite-bearing veins. These veins formed close to peak burial conditions at 30–60 km depth where deep slow slips

The origin of crystal-scale Zr isotopic variation remains enigmatic. Here, we report high-precision Zr isotopic compositions of thin-sectioned and hand-picked zircon crystals from monzodiorites and K-feldspar granites, which represent the mafic and felsic products of a differentiating magma. Our results reveal that zircons from both rock associations are dominated by a rim-ward increase in the 94Zr/90Zr