Mass concentration (mascon) solutions have become a prominent medium for investigating time-variable gravity recovered by GRACE and GRACE Follow-On. While GRACE Level-2 spherical harmonic products require various postprocessing techniques to eliminate correlated noise, mascon formulations employ spatial regularization strategies during the estimation step to improve signal recovery. However, mascon

Eastern Bangladesh sits on the seismically active Chittagong-Myanmar fold and thrust belt (CMFB), a north-trending accretionary wedge on the eastern side of the India-Eurasia collision. Earthquakes on the basal décollement and associated thrusts within the CMFB present a hazard to this densely populated region. In this study, we interpret 28 seismic reflection profiles from both published and unpublished

The 2016 M7.8 Kaikōura earthquake is one of the most complex earthquakes in recorded history, with significant rupture of at least 21 crustal faults. Using a matched-filter detection routine, precise cross-correlation pick corrections, and accurate location and relocation techniques, we construct a catalog of 33,328 earthquakes between 2009 and 2020 on and adjacent to the faults that ruptured in the

Probabilistic seismic hazard analysis (PSHA) is the standard method used for designing earthquake-resistant infrastructure. In recent years, several unexpected and destructive earthquakes have sparked criticism of the PSHA methodology. The seismological part of the problem is the true frequency-magnitude distribution of regional seismicity. Two major models exist, the Gutenberg-Richter (G-R) and the

We develop an automatic workflow for enhancing surface wave signals in ambient noise cross correlations (ANCs) calculated for a one-dimensional (1-D) linear array. The proposed array-based method is applied to a 1.6 km-long dense linear nodal array crossing surface traces of the San Jacinto fault near Anza, California. Fundamental and higher modes of surface waves are observed in ANCs of the nodal

Volcanoes are unstable structures that deform laterally and frequently experience mass wasting events. Hydrothermal alteration is often invoked as a mechanism that contributes significantly to volcano instability. We present a study that combines laboratory experiments, geophysical data, and large-scale numerical modeling to better understand the influence of alteration on volcano stability, using

Many volcanoes around the world are persistently active with continuous degassing for years or even centuries, sometimes exceeding historic records. Such long-term stability contrasts with short-term instability, reflected in eruptive episodes that punctuate passive degassing. These two aspects of persistent activity, long-term stability as opposed to short-term instability, are often conceptualized

Phyllosilicate minerals, due to their sheets structure and morphology, are known to cause anisotropy in bulk rock properties and make the bulk rock more compliant. Accurately characterizing the micromechanical behavior of phyllosilicate minerals from laboratory observations, which eventually translates to the bulk rock behavior, is still challenging due to their fine-grained nature. Recent advances

The Gulf of Lions - Ligurian basin, in the Western Mediterranean, opened from the end of Oligocene to the Miocene as a back-arc basin driven by rollback of the Ionian slab. Geophysical surveys across the margin have explored the crustal structure and the continent-ocean transition (COT), but its location and petrological nature is still a matter of debate. Here, we apply joint refraction and reflection

We present a new algorithm, ReversePetrogen (RevPet), to infer mantle melting conditions (pressure, temperature, source composition) using evolved basalts that have experienced multiphase fractional crystallization. RevPet measures and minimizes the compositional distance between experimentally predicted phase saturation boundaries and an erupted basalt and the more primitive liquids that return it

Beneath the continents and island arcs, a seismic discontinuity is often detected around 300 km depth, referred to as the X-discontinuity. Various mineralogical and petrological mechanisms have been put forth to explain its occurrence. Because of the large depth variability, it is challenging to explain its origin invoking a single mineralogical phase transition. In order to investigate this discontinuity

Quantifying the strength evolution of faults that cut the lithosphere is essential to better understand seismicity in continental regions. We estimate differential stresses and principal stress orientations driving rapid slip of ∼10 mm/yr on the active Mai'iu low-angle normal fault (LANF), SE Papua New Guinea. The fault's mafic footwall hosts a well-preserved sequence of mylonite, (ultra-)cataclasite

The filling and emptying cycles of reservoir operations may change hydrological mass loading, leading to a flexural deformation of the crust that may compromise the infrastructure safety or trigger earthquakes. In this study, we investigate the seasonal crustal response of the Tehri reservoir in the Garhwal Himalaya, northern India, using interferometric synthetic aperture radar (InSAR), Global Positioning

The multidecadal fluctuations in sea level changes play an important role in the exact quantification of present-day global mean sea level (GMSL) rise and its acceleration. Here, we use an array processing technique (optimal sequence estimation) to analyze 44 global tide gauge (TG) sea-level records with identical January 1933–December 2019 data spans. The results reveal for the first time a common

The Xainza-Dinggye rift, an approximately north-south trending Cenozoic fault zone across the Lhasa Terrane, is an ideal location to investigate extensional mechanisms in the upper crust and lithospheric deformation caused by the subducting Indian Plate beneath the central-southern Tibetan Plateau. The 3-D electrical resistivity structure was obtained by modeling magnetotelluric data from an array

The dynamics of high pressure (HP) and ultra-high pressure (UHP) rock exhumation in opposite-dip double subduction-collision systems remain enigmatic. Here, we present 3D thermo-mechanical numerical models to study the geodynamics of continental-margin subduction, collision, and crustal exhumation of HP-UHP metamorphic rocks in oppositely dipping adjacent subduction zones. In our model setups, an initial

Theoretical studies predict that during earthquake rupture faults slide at non-constant slip velocity, however it is not clear which source time functions are compatible with the high velocity rheology of earthquake faults. Here we present results from high velocity friction experiments with non-constant velocity history, employing a well-known seismic source solution compatible with earthquake source

Micro-crack density, porosity, and permeability in fault damage zones play an important role in the pore fluid diffusion process. During long-term earthquake cycles, those properties change with time as a result of either physical damage or chemical/physical healing. Hence, the evolution of permeability can affect the recurrence of earthquakes by either delaying or accelerating the weakening of the

An outcrop in the layered gabbro section from the Wadi Wariyah of the Oman ophiolite has been investigated to provide new insights into the hydrothermal activities that cover a large temperature range in the lower crust at fast-spreading mid-ocean ridges. Our observations reveal a complex veining system composed of gabbroic dikes, hydrous mineral (amphibole, epidote, prehnite) veins and associated

The 2004–2009 caldera uplift is the largest instrumentally recorded episode of unrest at Yellowstone caldera. We use GPS and Interferometric Synthetic Aperture Radar (InSAR) time series spanning 2004–2015, with a focus in the aforementioned event to understand the mechanisms of unrest. InSAR data recorded ∼25 and ∼20 cm of uplift at the Sour Creek (SCD) and Mallard Lake (MLD) resurgent domes during

Trace elements of quartz document the physical-chemical evolutions of quartz growth, which has been a great and most applied tool in the study of geological settings in quartz-forming environments. A classic method is using graphic diagram plots visualizing the quartz trace element discriminations and trends, examples including the Al-Ti diagram (Rusk, 2012, https://doi.org/10.1007/978-3-642-22161-3_14)

In extending volcanic arcs such as the Aegean, tectonic processes exert a significant control on magmatism. Spanning scales from 1 to 10s of km, volcanic vents, edifices, and eruptive centers follow the orientation of, and are located near, fault zones. Whether this tectonic control on magmatism results from individual faults/fractures weakening the crust or because regional stresses control magma

A new time series InSAR method is presented based on a strain model. Traditionally, the interferometric phases are optimized based only on a constant set of statistically homogeneous points throughout the observing period, and thus the decorrelated phase cannot be well recovered and possible incoherent (or coherent) phases are (are not) used to optimize the target phase. In the proposed method, a strain

Volcanoes undergoing unrest often produce displacements at the ground surface, providing an important window to interpret the dynamics of the underlying magmatic system. The thermomechanical properties of the surrounding host rock are expected to be highly heterogeneous, with key physical parameters having strong temperature dependence. Deformation models that incorporate non-elastic rheological behaviours

The petrogenesis of Himalayan leucogranites remains crucial for understanding the thermal and tectonic evolution of the Himalayan orogen. In order to understand whether they are largely pristine melts of crustal anatexis or have experienced intensive fractional crystallization, we present Fe isotopic data of 30 representative Himalayan leucogranites and 9 local metasedimentary rocks. Excepting three

Heat flow measurements collected throughout the Auka and JaichMaa ja' ag' hydrothermal vent fields in the central graben of the Southern Pescadero Basin, southern Gulf of California, indicate upflow of hydrothermal fluids associated with rifting dissipate heat in excess of 10 W/m2 around faults that have a few kilometers in length. Paradoxically, longer faults do not show signs of venting. Heat flow

No abstract is available for this article.

The radial viscosity of the mantle is generally thought to increase by ∼10-100 times from the upper to lower mantle with a putative, abrupt increase at 660 km depth. Recently, a low viscosity channel (LVC) between 660 and 1,000 km has been suggested. We conduct a series of time-dependent flow models with viscosity either increasing or decreasing at 660 km depth while tracking slab structure, state-of-stress

Underground traffic activities spread ground-borne vibrations in a complex way. The present work focuses on 173 individual vehicles tracked as moving sources of vibrations in the Mont Terri rock laboratory, located 95 m away from a motorway tunnel. Two neighboring geophones record the vertical ground velocity of traffic-induced events with peak particle velocities ranging in 0.15-0.35 m/s. A dynamic

Wudalianchi volcano is one of the youngest volcanic groups among the Cenozoic intraplate volcanoes in Northeast China and is notable for its potassium-rich basalts. With newly deployed dense broadband seismic stations, we construct a high-resolution 3-D S-wave velocity model of Wudalianchi volcano and its adjacent region, including the Keluo and Erkeshan volcanoes, using ambient noise and teleseismic

Size segregation is a common feature in geophysical mass flow deposits and is an active process during motion. The presence of interstitial fluids in such flows affect the motion of constituent particles and result in complex segregation behaviors. Effects of the viscosity and density of various interstitial fluids on the rate of particle size segregation are investigated through coupled granular-fluid

We experimentally examined the impact of supercritical carbon dioxide (scCO2) on fracture permeability and fracture surface characteristics in shales of various compositions. We measured permeability and fracture normal displacement at different effective stresses using both argon and scCO2 as pore fluids. Both natural fractures and saw cuts in intact samples were used in our study. The permeability

Earthquakes occur within complex fault zones containing numerous intersecting fault strands. This complexity poses a computational challenge for rupture models, which typically simplify fault structure to a small number of rough fault surfaces, with all other deformation assumed to be off-fault viscoplastic deformation. In such models, high-frequency ground motions originate solely from frictionally-mediated

The global navigation satellite system (GNSS) and gravity recovery and climate experiment (GRACE) are two independent geodetic technologies that can detect geometric and gravity deformations, respectively. The signals observed by the two technologies mainly include the internal tectonic movement and surface mass loading effects. The former generally exhibits a long-term stable linear trend, whereas

In many subduction zones, the plate interface hosts intermittent, low-frequency, low-magnitude seismic tremor and low-frequency earthquakes (LFEs). Seismic activity clusters in episodic bursts that migrate along the fault zone in complex ways. Geological structures in fossil tremor source regions testify to large and pervasive variations of fluid pressure and permeability. Here, we explore the potential

Salt basins often exhibit a shelf/slope region of extension and a deeper domain of contraction. The up-slope normal faults in such salt tectonics systems are often associated with the pinch-out edge of the buried salt layer. Although the spatial correlation between the normal faults and the salt pinch-out was previously observed, the mechanism was not fully explained. The Levant basin, which is a young

Isothermal remanent magnetization (IRM) curves are used widely in rock magnetic and environmental magnetic studies to characterize magnetic properties of natural samples. Previous theoretical and experimental investigations indicate that magnetostatic interactions can strongly affect the IRM behavior. In order to quantitatively investigate this effect, we modeled IRM curves and hysteresis properties

Réunion Island in the western Indian Ocean is well known as one of the most active volcanic hotspots on Earth. Its birth, Ma ago, created the Deccan volcanic traps in India (almost 2 million ), associated with the Cretaceous-Tertiary boundary and with the extinction of about 90% of life on the Earth, including dinosaurs. However, the deep structure of the underlying mantle, the potential presence of

The strong increase of seismicity rates in the contiguous USA over the last 10 years is linked to the injection of huge amounts of wastewater from oil and gas production in unconventional hydrocarbon reservoirs. We calculated 549 moment tensors of induced earthquakes (MW ≤ 4.9) in southern Kansas to study their source mechanisms and their relation to injection activity. Seventeen percent of the events

We estimate the rates and patterns of vertical land motion (VLM) on all locations on Earth's land surface using GPS Imaging. The solution is based on a large database of uniformly processed GPS data from solutions that are aligned to the International Terrestrial Reference Frame. We provide global maps and estimates of VLM at all tide gauges of the Permanent Service for Mean Sea Level to better constrain

The PLUM (Propagation of Local Undamped Motion) earthquake early warning (EEW) algorithm differs from typical source-based EEW algorithms as it predicts shaking directly from observed shaking without first deriving earthquake source information (e.g., magnitude and epicenter). Here, we determine optimal PLUM event detection thresholds for U.S. West Coast earthquakes using two data sets: 558 M3.5+ earthquakes

The left-lateral Xianshuihe Fault is located at the eastern boundary of the Tibetan Plateau and is one of the most active faults in China. It is associated with substantial seismic potential, with more than 20 Mw > 6 earthquakes since 1700. The fault has been documented to be creeping at the surface for decades; however, the spatial and temporal distributions of shallow creep along the fault are not

The final version of the above article was posted prematurely on 16 July 2021, owing to a technical error. The final, corrected version of record will be made fully available at a later date.

We present a model of radial anisotropy in the crust and upper mantle of East Asia from a combination of new group velocity measurements and previously published surface wave dispersion data sets. Our combined data set ranges 5–375 s period and contains dispersion data up to the fifth overtone. We directly relate the data to variations in isotropic and radially anisotropic shear wave crustal and mantle

Machine learning (ML) techniques have become increasingly important in seismology and earthquake science. Lab-based studies have used acoustic emission data to predict time-to-failure and stress state, and in a few cases, the same approach has been used for field data. However, the underlying physical mechanisms that allow lab earthquake prediction and seismic forecasting remain poorly resolved. Here

Kinematic finite-fault source inversions aim at resolving the spatio-temporal evolution of slip on a fault given ground motion recorded on the Earth's surface. This type of inverse problem is inherently ill-posed due to two main factors. First, the number of model parameters is typically greater than the number of independent observed data. Second, small singular-values are generated by the discretization

On January 11, 2018 (18:26 UTC), a Mw 6.0 earthquake occurred approximately 30 km west of the Sagaing Fault in the Bago-Yoma Range (BYR). Using a local broadband seismic network and regional seismic stations, we refine the locations and moment tensors of the earthquake sequence. We relocate 98 earthquake epicenters and determine the focal mechanism and centroid depth of the mainshock and 20 aftershocks

We develop finite element models of the coseismic displacement field accounting for the 3D elastic structures surrounding the epicentral area of the 2019 Ridgecrest earthquake sequence containing two major events of Mw7.1 and Mw6.4. The coseismic slip distribution is inferred from the surface displacement field recorded by interferometric synthetic aperture radar. The rupture dip geometry is further

Inelastic wedge deformation likely plays an important role in the generation of tsunami and ocean acoustic waves in accretionary subduction margins. In an elastic dislocation model, whether or not the fault breaks the trench has a significant effect on seafloor deformation and resulting tsunami. However, this boundary condition is less important when significant inelastic deformation in the overriding

Based on the assumption that fault slip dominates in the stress relaxation in the brittle crust, Coulomb theory allows for the crustal stress estimation with an empirical frictional coefficient. However, natural variability of fault friction and slip uncertainty exist in the Earth's crust. To address the extent to which heterogeneous frictional slips influence crustal stress and its evolution, we establish

Processes for formation, cooling, and altering Earth's ocean crust are not yet completely understood due to challenges in access and sampling. Here, we use contiguous micro-imaging infrared spectroscopy to develop complete-core maps of mineral occurrence and investigate spatial patterns in the hydrothermal alteration of 1.2 km of oceanic crust recovered from Oman Drilling Project Holes GT1A, GT2A,

In this article, we validate the neuro-fuzzy kinematic finite-fault inversion method by studying the rupture process of the , 24/Aug/2016, Amatrice, central Italy, earthquake. We jointly invert three different datasets to infer the spatio-temporal slip distribution, namely static and high-rate GNSS data ( Hz) and strong-motion data ( Hz). Each dataset is used to constrain a different frequency range

In a controlled-source seismology, the standard full waveform inversion (FWI) can’t reliably recover the macrovelocity structure in the deep part, if the surface seismic data lack of ultra-long offsets and very low frequencies. Reformulating the FWI for pre-critical reflections based on model scale separation leads to reflection full waveform inversion (RWI), which aims to improve the reconstruction

The geodynamic evolution of the Western Mediterranean for the past 35 My is a matter of debate. Present-day structure and composition of the lithosphere and sublithospheric mantle may help in constraining the geodynamic evolution of the region. We use an integrated geophysical-petrological modeling to derive and compare the present-day thermal, density and compositional structure of the lithosphere

In a previous study, a new snapshot modeling concept for the archeomagnetic field was introduced (Mauerberger et al., 2020, https://doi.org/10.1093/gji/ggaa336). By assuming a Gaussian process for the geomagnetic potential, a correlation-based algorithm was presented, which incorporates a closed-form spatial correlation function. This work extends the suggested modeling strategy to the temporal domain

The uplift of the southern African Plateau with its average elevations of ∼1,000 m is often attributed to mantle processes, but there are conflicting theories for the timing and drivers of topographic development. Evidence for most proposed plateau development histories is derived from continental erosion histories, marine stratigraphic architecture, or landscape morphology. Here we use a landscape

From California to British Columbia, the Pacific Northwest coast bears an omnipresent earthquake and tsunami hazard from the Cascadia subduction zone. Multiple lines of evidence suggests that magnitude eight and greater megathrust earthquakes have occurred - the most recent being 321 years ago (i.e., 1700 A.D.). Outstanding questions for the next great megathrust event include where it will initiate

Hydrostatic pressure exerted by the ocean water column fundamentally influences magmatic and hydrothermal processes in submarine volcanic settings and is therefore an important parameter to know when investigating such processes. Currently, there are few reliable methods for reconstructing past ocean depths for ancient volcanic terranes. Here, we develop and test an empirically calibrated statistical

Southern New England exhibits diverse geologic features resulting from past tectonic events. These include Proterozoic and early Paleozoic Laurentian units in the west, several Gondwana-derived terranes that accreted during the Paleozoic in the east, and the Mesozoic Hartford Basin in the central part of the region. The Seismic Experiment for Imaging Structure beneath Connecticut (SEISConn) project

Icequakes, microseismic earthquakes at glaciers, offer insights into the dynamics of ice sheets. For the first time in the Antarctic, we explore the use of fiber optic cables as Distributed Acoustic Sensors (DAS) as a new approach for monitoring basal icequakes. We present the use of DAS for studying icequakes as a case study for the application of DAS to microseismic datasets in other geological settings