The Nankai subduction zone presents significant seismic and tsunami risks, given its historical earthquakes exceeding magnitude 8 and the expectations of similar future events. Slow earthquakes, common at the shallow and deep plate interface, result from different frictional properties linked to interplate slip deficit accumulation. This study estimates slip deficit rates at the Nankai subduction zone

Mineral chemistry records the pressure and temperature conditions of lithospheric processes. Active tectonic margins, however, are subjected to non-hydrostatic stresses wherein stress magnitudes vary directionally, and the impact of non-hydrostatic stress on mineral chemistry is uncertain. The work of materials scientists F. Larché and J. Cahn provides a framework for quantifying how stress affects

Semi-brittle and plastic deformation behaviors of mafic granulite are significant for evaluating characteristics of ductile zones in the lower crust region and the rheological strength of the lower crust. Axial compression experiments were carried out in this study with natural mafic granulite collected from the North China Craton, using a gas medium apparatus at 950–1,150°C and 300 MPa with strain

We describe the development and assessment of a new terrestrial reference frame (TRF) based on a combination of geodetic techniques at the observation level over the period 2010–2022. Included in the solution are observations from the Global Positioning System (GPS), Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI). A key feature of our solution strategy is the use of space

The first three-dimensional (3-D) P and S wave attenuation (Qp and Qs) tomography of the crust and upper mantle of the northern Sumatra subduction zone is determined. We adopt an improved calculation scheme to precisely measure attenuation factor t* values from velocity amplitude spectral ratios among different stations that recorded the same earthquake. Our tomographic results show that the forearc

Sabancaya volcano (Peru), is a stratovolcano in the Central Volcanic Zone of the Andes. Since November 2016, it has been in constant activity, marked by daily multiple Vulcanian explosions. In this contribution, we first characterize the plumes generated by the explosions using visible- and infrared-wavelength imagery, describing plume morphologies and quantifying rise rates. Through an analysis of

Understanding volcanic eruption triggers is critical toward anticipating future activity. While internal magma dynamics typically receive more attention, the influence of external processes remains less understood. In this context, we explore the relationship between seasonal snow cycles and eruptive activity at Ruapehu, New Zealand. This is motivated by apparent seasonality in the eruptive record

To refine the melting curve, equation of state, and physical properties of MgO we performed plate impact experiments spanning ∼${\sim} $170–250 GPa on <100>${< } 100 > $ MgO single crystals, preheated to 2300 K. A controlled thermal gradient in ∼${\sim} $20 mm long samples enabled radiative temperature (±$\pm $3%–4%) and rarefaction overtake observations (yielding sound speed ±$\pm $2%) close to the

In tight crystalline rocks faults are known to be substantially more hydraulically conductive than the rock matrix. However, most of our knowledge relies on static measurements, or before/after failure data sets. The spatio-temporal evolution of the permeability field during faulting remains unknown. Here, we determine at which stage of faulting permeability changes most, and the degree of permeability

To examine the microstructural evolution that occurs during transient creep, we deformed samples of polycrystalline olivine to different strains that spanned the initial transient deformation. Two sets of samples with different initial grain sizes of 5 μm and 20 μm were deformed in torsion at T = 1,523 K, P = 300 MPa, and a constant shear strain rate of 1.5 × 10−4 s−1, during which both sets of samples

Interactions between multiple-scale thermochemical heterogeneities in the lowermost mantle, specifically ultralow velocity zones (ULVZs) and large low shear velocity provinces (LLSVPs), are critical in lower mantle dynamics. However, the evolution of ULVZs formed outside LLSVPs has not been thoroughly explored. Here we perform two-dimensional numerical experiments to examine the evolution of highly

Scattering of elastic waves causes velocity dispersion, which increases uncertainty in seismic analysis. Understanding the sources of scattering and the degree of velocity dispersion are critical to improve subsurface imaging in efforts to locate resources and study subsurface processes. In addition to scattering, other mechanisms, such as the wave-induced fluid flow in saturated rocks cause velocity

Teleseismic waveforms contain abundant interpretable information about Earth's properties. They can be used to explore the refined structure of Earth's interior, especially in the regions with imbalanced spatial distribution of seismic activity. However, it's technically infeasible to numerically simulate high-frequency (>1 Hz) teleseismic wave propagation within a whole domain iteratively in full-waveform

The hydraulic fracturing process is a prominent example of fracture network evolution under stress. However, the interactions between hydraulic fractures and natural fracture networks, along with the connectivity evolution of the resultant fracture networks, require more research. This research incorporates discrete fracture networks to characterize subsurface structures and employs the Discrete Element

On 18 November 2022, a large earthquake struck offshore southern Sumatra, generating a tsunami with 25 cm peak amplitude recorded at tide gauge station SBLT. Our W-phase solution indicates a shallow dip of 6.2°, compatible with long-period surface wave radiation patterns. Inversion of teleseismic body waves indicates a shallow slip distribution extending from about 10 km deep to near the trench with

Small-scale scatterers in the lower mantle contain key information on the recycling process in the whole mantle. Resolving the fine structures of these scatterers is crucial for understanding the dynamic evolution in the deep Earth. Here, we search for scatterers in the lower mantle beneath Central America and the northwestern Pacific Ocean by events in South America and PKP recordings in Japan. In

Geological interpretations, earthquake source inversions and ground motion modeling, among other applications, require models that jointly resolve crustal and mantle structure. With the second generation of the Collaborative Seismic Earth Model (CSEM2), we present a global multi-resolution tomographic Earth model that serves this purpose. The model evolves through successive regional- and global-scale

The Ediacaran Period, immediately following the Neoproterozoic Cryogenian glaciations, marked a crucial phase in the Earth's evolutionary history. The paleo-oceanic environment helped shape the habitability, yet the links between oceanic redox state, hydrochemistry, biological activity, and elemental cycling during this time remain poorly understood. Here, we address this scientific issue based on

The North Anatolian Fault (NAF) extends for over 1,000 km across Türkiye and poses significant seismic hazard in the region. The Main Marmara Fault (MMF) segment of the NAF in the Sea of Marmara (NW Türkiye), exhibits along-strike segmentation in its interseismic strain accumulation. Constraining the lithospheric configuration below the MMF is critical to understand its segmentation and assessing seismic

The understanding of the spatial-temporal distribution of past earthquakes is essential to assess the event recurrence behavior and to estimate the size of potential earthquakes along active strike-slip fault systems. However, the scarcity of paleoseismic data remains a major hurdle in this endeavor. This is the case of the longest strike-slip fault in Asia, the Altyn Tagh Fault (ATF). We documented

Several regularly recurring moderate-size earthquakes motivated dense instrumentation of the Parkfield section of the San Andreas fault (SAF), providing an invaluable near-fault observatory. We present a seismo-geodetic dynamic inversion of the 2004 Parkfield earthquake, which illuminates the interlinked complexity of faulting across time scales. Using fast-velocity-weakening rate-and-state friction

Krauklis waves are generated by pressure disturbances in fluid-filled cavities and travel along the solid-fluid interface. Their far-field radiation, observed in seismic data from volcanoes or hydraulic fracturing, is known as long-period events. Characterized by low velocity and resonance, Krauklis waves help estimate fracture size and discern fluids in saturated fractures. Despite numerous theoretical

Hydrous Fe3+-bearing bridgmanite (Bdg) is potentially a critical water host in the lowermost mantle. The spin transition behaviors of such materials are pivotal for understanding geophysical heterogeneity in the deep Earth but are poorly understood. Here, we investigated the spin transition and related geophysical properties of Fe3+ with associated H defects [Fe3+-H] at high P-T conditions using first-principles

Microcontinents are globally recognized as continental regions partially or entirely surrounded by oceanic lithosphere. Due to their positioning, they may become entangled in subduction zones and undergo either accretion or subduction. High-pressure metamorphism in subducted continental rocks supports the idea that microcontinents can be subducted, regardless of their low densities. In this study,

The formation and evolution of arc-backarc systems govern crustal production in some of the most volcanically and hydrothermally active environments on Earth. This study presents the first complete three-dimensional density model of the active arc-backarc system in the southwest Pacific comprising the Lau Basin and Tofua arc. Seafloor density and crustal thickness maps reveal changes in crustal composition

Many of the world's rifts and rifted margins have developed within former orogens. The South China Sea (SCS) formed during Cenozoic rifting by utilizing pre-existing orogenic structures, like thrust faults, thickened crust, and corresponding thermal weaknesses. The mechanisms explaining how inherited structures influence the spatiotemporal evolution of a rift remain a topic of on-going research. Here

Decades of geophysical monitoring have revealed the importance of slow aseismic fault slip in the release of tectonic energy. Although significant progress have been made in imaging aseismic slip on natural faults, many questions remain concerning its physical control. Here we present an attempt to study the evolution of aseismic slip in the controlled environment of the laboratory. We develop a kinematic

The dynamics of Earth's D″ layer at the base of the mantle plays an essential role in Earth's thermal and chemical evolution. Mantle convection in D″ is thought to result in seismic anisotropy; therefore, observations of anisotropy may be used to infer lowermost mantle flow. However, the connections between mantle flow and seismic anisotropy in D″ remain ambiguous. Here, we calculate the present-day

The India–Eurasia continental collision zone (IECCZ) is an ideal setting for studying plate collision processes, plateau uplift mechanisms, and orogenic activities. Several models have attempted to explain the north–south (N‒S) collision and east–west (E‒W) extension based on geological and geophysical observations. Among them, the subduction of the subducted Indian lower crust (SILC) and the deep

Utilizing existing telecommunication cables for Distributed Acoustic Sensing (DAS) experiments has eased the collection of seismological data in previously difficult-to-access areas such as the ocean bottom. To assess the potential of submarine DAS for monitoring seismic activity, we conducted an experiment from mid-October to mid-December 2021 using a 45 km long dark fiber extending from the Greek

Submarine calderas with active magma supply have recently been identified as potential sources of volcanic tsunamis due to sudden meter-scale uplift by trapdoor faulting, occurring every few years to a decade. These trapdoor uplifts are seismically recorded as non-double-couple earthquakes with magnitudes M > 5. Kita-Ioto Caldera, a submarine caldera in the Izu-Bonin arc, caused such earthquakes every

The central North China Craton (NCC) acts as a transition zone between the stable western and reworked eastern NCC. It is characterized by high seismic activity and experienced volcanic activity with small magma volumes. To assess the dynamic processes of the central NCC, particularly in a zone marked by intense differential tectonic deformation, we have obtained a 3-D radial anisotropic model of crust

No abstract is available for this article.

Seafloor massive sulfide (SMS) deposits in different geological settings can have variable magnetic mineralogy, but the mechanism and implications of their spatiotemporal diversity are poorly understood. Based on seabed shallow drilling and surficial sampling of the Yuhuang hydrothermal field, Southwest Indian Ridge, we investigate here whether ubiquitous oxidative weathering affects the magnetic properties

This study investigates the fundamental properties of shallow aragonite-component dominant porous coral reef limestone (CRL) to investigate its micromechanical properties and micrometer-scale pore dissolution characteristics. Nanoindentation tests were performed to assess changes in mechanical properties before and after dissolution. A novel numerical model, integrating the level-set method (LSM),

Kīlauea Volcano on Hawai'i Island is host to a complex volcanic and interwoven fault system. Over the last ∼120 years, a range of seismic events, including large earthquakes such as the 1975 Mw${M}_{w}$7.7 Kalapana earthquake, creep, and slow slip events, have occurred along the décollement underlying Kilauea's south flank. We explore both the deformation and stress changes of Kīlauea from 1896 to

A shallow sub-seafloor seismic model that includes well-determined seismic velocities and clarifies sediment-crust discontinuities is needed to characterize the physical properties of marine sediments and the oceanic crust and to serve as a reference for deeper seismic modeling endeavors. This study estimates the seismic structure of marine sediments and the shallow oceanic crust of the Alaska-Aleutian

Volcano deformation models contribute to hazard assessment by simulating magma system dynamics. Traditional magma reservoir pressure source shape assumptions often fail to replicate irregular, geophysically identified geometries. Uncertainties regarding the influence of reservoir geometry can limit the effectiveness of using deformation models to decipher unrest signals. Here, we aim to determine the

The role of solid Earth tide in fault reactivation has significant implications for understanding earthquake triggering, carbon sequestration, and the global carbon budget. Despite extensive research on this topic, the relationship between Earth tide and fault reactivation remains unclear. In this study, we investigate the influence of solid Earth tide on the reactivation of sub-seabed faults, which

Studying the subsurface structure of volcanoes is crucial for understanding volcanic mechanisms, current status, and potential risks. However, the intricate physical and chemical processes occurring over geological timescales make it challenging to characterize subsurface features such as volcanic structures and hydrothermal systems. Given the highly attenuating nature of magma, 3-D scattering and

Talc is expected to be an important water carrier in Earth's upper mantle, and understanding its electrical and seismic properties under high pressure and temperature conditions is required to detect possible talc-rich regions in subduction zones imaged using geophysical observations. We conducted acoustic and electrical experiments on natural talc aggregates at relevant pressure-temperature conditions

Faulting and folding of basement rocks together accommodate convergence within continental orogens, forming complex zones of intraplate deformation shaped by the fault interaction. Here we use the river terraces along the Dongda river to examine the tectonic deformation patterns of the hinterland and the foreland of the eastern North Qilian Shan, a zone of crustal shortening located at the northeast

Offset geomorphic markers are commonly used to interpret slip history of strike-slip faults and have played an important role in forming earthquake recurrence models. These data sets are typically analyzed using cumulative probability methods to interpret average amounts of slip in past earthquakes. However, interpretation of the geomorphic record to infer surface slip history is complicated by slip

In this paper, we present numerical modeling aimed to explain Deep Long Period (DLP) events occurring in middle-to-lower crust beneath volcanoes and often observed in association with volcanic eruptions or their precursors. We consider a DLP generating mechanism caused by the rapid growth of gas bubbles in response to the slow decompression of H2O–CO2 over-saturated basaltic magma. The nucleation and

Rare bedrock exposures of the eastern Denali fault zone in southwestern Yukon allow for the measurement, sampling, and analyses of brittle regime fault slip data and deformation mechanisms to explore relations to far field, oblique plate motions. Host rock lithologies and associated slip surfaces show episodic damage zone-related deformation and calcite ± hematite ± chlorite related hydrothermal fluid

We performed a series of hydraulic stimulations at 1.1 km depth in the Bedretto underground laboratory, Switzerland, as part of an overall research strategy attempting to understand induced seismicity on different scales. Using an ultra-high frequency seismic network we detect seismic events as small as Mw < −4, revealing intricate details of a complex fracture network extending over 100 m from the

In basaltic eruptions, bubbles move freely and collide within a volcanic conduit, leading to frequent bubble coalescence. Understanding the dynamics of buoyancy-driven coalescence of bubbles is crucial for predicting the explosivity of basaltic eruptions. We examine the evolution of the bubble volume distribution while considering buoyancy-driven coalescence and expansion due to decompression. We find

It remains controversial whether the interaction between a mantle plume and a craton destabilizes or reinforces the craton. The Tarim basin, with a craton core, a Permian Large Igneous Province, and internal deformation, is an ideal place to investigate this interaction. Here, we construct high-resolution S-wave velocity structures down to 15 km in depth using multi-frequency receiver functions from

Full waveform inversion (FWI) creates high resolution models of the Earth's subsurface structures from seismic waveform data. Due to the non-linearity and non-uniqueness of FWI problems, finding globally best-fitting model solutions is not necessarily desirable since they fit noise as well as the desired signal in data. Bayesian FWI calculates a so-called posterior probability distribution function

Distributed acoustic sensing (DAS) is an innovative technology with great potential for acquiring seismic data sets in urban areas. In this work, we check the suitability of a DAS data set acquired in Granada (Spain) for retrieving subsurface reflectivity from ambient noise. The fiber-optic is a pre-existing underground telecommunication cable that crosses the city from Northwest to Southeast. We use

In subduction zones, along-strike and downdip variations in megathrust slip behavior are linked to changes in properties of the subducting and overriding plates. Although marine geophysical methods provide insights into subduction zone structures, most surveys consist of sparse 2D profiles, limiting our understanding of first-order controls. Here, we use active-source seismic data to derive a 3D crustal-scale

The Lhasa terrane in southern Tibet occupies a central position in Asian tectonics, yet its pre-Mesozoic petrologic and tectonic evolution is poorly constrained, especially the Southern Lhasa subterrane (SLS). Here, new zircon U–Pb ages, zircon trace element and Hf isotopic compositions, and whole-rock geochemical data for mafic meta-igneous rocks from the SLS distinguish three tectono-thermal events

The region of northern Borneo in South East Asia sits within a post-subduction setting formed by the recent termination of two sequential but opposed subduction systems. In this study we use seismic data from a recent temporary array deployment to image the crustal velocity structure beneath northern Borneo using a two-stage Bayesian trans-dimensional tomography scheme, in which period dependent phase

Precambrian paleomagnetic studies are critical for testing paleogeographic reconstructions in deep time but rely on the fidelity of the assumption of the geocentric axial dipole (GAD) hypothesis. With high-reliability data from mafic dykes and volcanic rocks, the scatter of individual virtual geomagnetic poles (VGPs) can be used to test simple GAD models. In order to conduct such a test, the VGPs must

Understanding postseismic processes following the 2016 Mw 7.8 Kaikōura earthquake remains challenging due to the time-dependent afterslip over the complex forearc system including crustal faults and megathrust, and the viscoelastic relaxation of the upper mantle. How the 2016 Mw 7.8 Kaikōura crustal earthquake interacts with the megathrust has yet to be better understood. Here we have derived the first

We apply the Matrix Profile algorithm to 100 days of continuous data starting 10 days before the 2019 M 6.4 and M 7.1 Ridgecrest earthquakes from borehole seismic station B921 near the Ridgecrest aftershock sequence. We identify many examples of reversely polarized waveforms, but focus on one particularly striking earthquake pair with strongly negatively correlated P and S waveforms at B921 and several

Recently, a widespread and densely continuous-recording ocean-bottom seismograph network has been deployed in the Japan Trench subduction zone. Utilizing the offshore network data improves azimuthal station coverage for offshore earthquakes in the Japan Trench subduction zone. It has a potential to obtain centroid moment tensor (CMT) solutions more accurately than conventional analyses using onshore

The Dʺ layer, defined as 200–400 km in the lowermost mantle, is a thermal and chemical boundary layer between the solid silicate mantle and the liquid outer core. Deciphering the detailed structures of the Dʺ region is essential for unlocking the thermal and chemical states in the deep Earth. Here, we precisely measure the slowness and back-azimuth of the direct P-waves by beamforming based on the

In this study, we reveal the deformational structure of the crust of the northern part of the Ryukyu Arc and Okinawa Trough using ambient noise tomography. Compared with southern Ryukyu, the northern segment exhibits a wide and shallow basin, a crust without localized thinning, slow extension rates, and highly arc-oblique, right-lateral retreat of the Ryukyu Arc. We present both isotropic and azimuthally

We investigate the dynamic interactions between the Southern San Andreas Fault (SSAF) and a proximal normal fault (NF) beneath the Salton Sea in southern California. The NF, positioned near the SSAF terminus at Bombay Beach, exhibits 11–15 displacement events across 14 stratigraphic sequences, with a range of 0.2–1.4 m of vertical offset since ∼2–3 ka. Notably, four of these events may align temporally