JGR–Solid Earth

We present a new geodetic strain rate and rotation rate model for Greece that has been derived using a highly dense GPS velocity field. The spatial distribution and the resolved rates of the various velocity gradient tensor quantities provided updated constraints on the present-day upper crustal deformation in the region and revealed new details not reported previously. The spatial distribution of the second invariant demonstrated that the overall magnitude of strain rates is highest across two well-defined provinces. The first follows the North Anatolian Fault and its two branches within the north Aegean, crosses central Greece and through the Gulf of Corinth it terminates in western Greece, while the second encompasses the extensional province of western Turkey and the eastern Aegean Sea islands. Our estimates revealed that shearing affects some of the fault-bounded grabens of central Greece that lie to the SW of the North Aegean Basin implying considerable oblique extension. We identified a narrow region of counterclockwise rotation whose location and kinematics have been induced by the net effect across the intersection of the clockwise rotating domains of western and central Greece. The Aegean microplate and the Anatolian plate are separated by a wide transition zone which accommodates the curved stretching of the entire plate system. In both edges of the Hellenic forearc the dominant mode of crustal strain is E-W extension. We found that earthquakes of M ≥ 5.6 are spatially well-correlated with high-strain areas, indicating that strain rate mapping could be used to inform future probabilistic seismic hazard analyses.

The CsCl-type (B2) phase of FeSi (B2-FeSi) has been proposed as a candidate phase in the ultralow-velocity zones (ULVZs) at the base of the lower mantle and in the Earth's inner core. However, the elastic properties of B2-FeSi under relevant conditions remain unclear. Here we determine the density, elastic constants, and velocities of B2-FeSi at high pressures (90–390 GPa) and temperatures (3,000–6,000 K) relevant to the Earth's lower most mantle and the inner core, using first-principles molecular dynamics simulations. At the base of the lower mantle, B2-FeSi shows significantly lower velocities and a higher density than those of the ambient mantle. Mechanical mixing models suggest the presence of ∼27–39 vol% B2-FeSi in the silicate mantle is consistent with the reduced velocities and the elevated density of ULVZs observed seismically. On the other hand, the hcp-Fe and B2-FeSi mixture exhibits higher bulk sound velocity compared to the PREM under inner core conditions. Adding superionic H in the interstitial sites of B2-FeSi lowers its density but has little effect on the bulk sound velocity of B2-FeSi, precluding H-bearing B2-FeSi as a major component in the Earth's inner core.

Fault zones exhibit 3D variable thickness, a feature that remains inadequately explored, particularly with regard to the impact on fluid flow. Upon analyzing an analytic solution, we examine 3D thermal-hydraulic (TH) dynamical models through a benchmark experiment, which incorporates a fault zone with thickness variations corresponding to realistic orders of magnitude. The findings emphasize an area of interest where vigorous convection drives fluid flow, resulting in a temperature increase to 150°C at a shallow depth of 2.7 km in the thickest sections of the fault zone. Moreover, by considering various tectonic regimes (compressional, extensional, and strike-slip) within 3D thermal-hydraulic-mechanical (THM) models and comparing them to the benchmark experiment, we observe variations in fluid pressure induced by poroelastic forces acting on fluid flow within the area of interest. These tectonic-induced pressure changes influence the thermal distribution of the region and the intensity of temperature anomalies. Outcomes of this study emphasize the impact of poroelasticity-driven forces on transfer processes and highlight the importance of addressing fault geometry as a crucial parameter in future investigations of fluid flow in fractured systems. Such research has relevant applications in geothermal energy, CO2 storage, and mineral deposits.

We monitored the time history of the velocity change (dv/v) from 2002 to 2022 to investigate temporal changes in the physical state near the Parkfield Region of the San Andreas Fault throughout the interseismic period. Following the coseismic decrease in dv/v caused by the 2003 San Simeon (SS) and the 2004 Parkfield earthquakes, the dv/v heals logarithmically and shows a net long-term increase in which the current dv/v level is equivalent to, or exceeding, the value before the 2003 SS earthquake. We investigated this long-term trend by fitting the model accounting for the environmental and coseismic effects to the channel-weighted dv/v time series. We confirmed with the metrics of Akaike information criterion and Bayesian information criterion that the additional term of either a linear trend term, or a residual healing term for the case where the healing had not been completed before the SS earthquake occurred, robustly improved the fit to the data. We eventually evaluated the sensitivity of the dv/v time history to the GNSS-derived strain field around the fault. The cumulative dilatational strain spatially averaged around the seismic stations shows a slight extension, which is opposite to what would be expected for an increase in dv/v. However, the cumulative rotated axial strain shows compression in a range near the maximum contractional horizontal strain (azimuth of N35°W to N45°E), suggesting that the closing of pre-existing microcracks aligned perpendicular to the axial contractional strains would be a candidate to cause the long-term increase observed in the multiple station pairs.

We have extended the distributional finite difference method (DFDM) to simulate the seismic-wave propagation in 3D regional earth models. DFDM shares similarities to the discontinuous finite element method on a global scale and to the finite difference method locally. Instead of using linear staggered finite-difference operators, we employ DFDM operators based on B-splines and a definition of derivatives in the sense of distributions, to obtain accurate spatial derivatives. The weighted residuals method used in DFDM's locally weak formalism of spatial derivatives accurately and naturally accounts for the free surface, curvilinear meshing, and solid-fluid coupling, for which it only requires setting the shear modulus and the continuity condition to zero. The computational efficiency of DFDM is comparable to the spectral element method (SEM) due to the more accurate mass matrix and a new band-diagonal mass factorization. Numerical examples show that the superior accuracy of the band-diagonal mass and stiffness matrices in DFDM enables fewer points per wavelength, approaching the spectral limit, and compensates for the increased computational burden due to four Lebedev staggered grids. Specifically, DFDM needs 2.5 points per wavelength, compared to the five points per wavelength required in SEM for 0.5% waveform error in a homogeneous model. Notably, while maintaining the same accuracy in the solid domain, DFDM demonstrates superior accuracy in the fluid domain compared to SEM. To validate its accuracy and flexibility, we present various 3D benchmarks involving homogeneous and heterogeneous regional elastic models and solid-fluid coupling in both Cartesian and spherical settings.

Large block-bounding faults on the Tibetan plateau are significant geological structures that accommodate tectonic movements and accumulate stress, leading to large earthquakes. Quantifying the interseismic slip deficit rate helps to better assess the earthquake potential. We combine available InSAR (2015–2020) and interseismic GPS data to determine fault coupling along 14 major block-bounding faults. Spatially dense InSAR measurements remarkably improve the resolution of the coupling model. Combined with a GPS-constrained block model, we examine the performance of the inversion approach with the stress constraint and the common Laplacian smoothing based on both synthetic tests and real data. We suggest that, for continental strike-slip faults, adding the stress constraint can mitigate unphysical coupling distributions due to unreasonable assumptions or modeling artifacts, reducing the model uncertainty and improving the accuracy of the coupling model. This is particularly useful for segments featured by a highly heterogeneous distribution of coupling along the transition zone from locking to creeping region, partially-coupling segment, and junction zone between main and subsidiary faults. We present a large-scale fault coupling map along the major block-bounding faults on the northeastern and eastern Tibetan plateau, highlighting the distinct degrees of fault coupling and lateral variations. The collage of coupling maps along different faults demonstrates the kinematic features over a broad time scale during earthquake cycles ranging from early to late interseismic phases, such as the segments ruptured during the 2001 Kokoxili earthquake and the 1920 Haiyuan earthquake.

Surface topography is an important yet largely neglected aspect of the early evolution of cratons. The lateral accretion of cratonic nuclei inevitably forms orogenic belts that subsequently provide a sediment source for large, resource-rich intracratonic basins, but to date, geodynamic models have focused exclusively on lithospheric root processes. Here we use two-dimensional thermal-mechanical models to study the topography and lithospheric deformation during 50 Myr of compression of a cratonic nucleus, to simulate the lateral accretion phase of craton growth in the Neoarchean. Although the cratonic nucleus thickens slightly during the compression phase, most of the deformation occurs in the regions adjacent to the nucleus that have weaker lithosphere. Here, crustal thickness triples developing high topography in excess of 10 km without active erosion. Models with different initial rheological parameters will have different final topography and lithosphere geometry, but in general it is difficult to shorten and deform the depleted cratonic nucleus, unless there are significantly weak heterogeneities in the mantle lithosphere. We apply two quantitative analysis techniques to objectively evaluate a multitude of model outputs. Cross-correlation clustering (CCC) measures the degree of similarity between topography profiles and categorizes models based on the general topographic character. Six different topography families are possible in the context of our models and crustal strength is the most important parameter affecting the shape. From principal component analysis (PCA) we identify four dominant lithosphere geometries. When used together, these two methods provide distinct yet complementary information about the surface and subsurface deformation features in our models.

Clay-rich rocks are integral to subduction zone dynamics and of practical importance, for example, as barriers in nuclear waste and CO2 repositories. While the effects of swelling strain on the self-sealing capabilities of these rocks are relatively well-established, the implications of polar fluids interacting with charged clay particles on the frictional behavior, and the role of swelling stress in initiating slip in critically stressed faults, remain ambiguous. To address these uncertainties, we conducted triaxial friction experiments using saw-cut samples, with the upper half composed of Opalinus claystone (OPA) and the lower half of Berea sandstone (BER). The frictional strength of the non-wetted OPA-BER interface was estimated based on experiments at confining pressures of 4–25 MPa and constant axial loading rate (0.1 mm/min). Fluid injection friction experiments were performed using decane (non-polar fluid) or deionized water (polar fluid) at 10 and 25 MPa confining pressures and constant piston displacement control. Macroscopic mechanical data were complemented by distributed strain sensing on the sample surface. Compared to decane, the frictional strength of the OPA-BER interface tended to decrease when injecting water, which is attributed to phyllosilicate lubrication and the transition of the OPA from a solid rock to an incohesive mud near the saw-cut surface. When injecting water, slip was initiated during initial hydration of the OPA-BER interface, although the apparent stress state was below the yield stress. To explain this behavior, we propose that the swelling stress is a crucial factor that should be integrated into the effective stress model.

Crack interactions leading to shear localization were quantified using microstructural analysis for brittle faults and high-temperature ductile faults formed during experiments on quartz sandstone. In both faulting regimes, the nucleation of macroscopic faults results from the interactions of microfractures at two length scales in ensemble. Brittle faults nucleate when the longest mesoscale shear fractures and transgranular tensile cracks critically interact. In contrast, ductile faults nucleate when the longest mesoscale shear fractures and multi-grain scale intergranular shear cracks critically interact. For both faulting regimes, we conclude the interaction and coalescence of the longest mesoscale shear fractures is the fundamental process responsible for fault nucleation. Hence, mesoscale shear fractures, which accommodate the majority of axial strain prior to shear localization in both faulting regimes, also serve as the nucleus of macroscopic faults. Locally, the growth of the mesoscale shear fractures is promoted by the interaction and coalescence of the multi-grain scale cracks in both faulting regimes. We hypothesize that attainment of a critical microstructure for shear localization (i.e., local clustering of the longest microfractures) requires a characteristic amount of plastic axial strain, which depends on deformation conditions. In brittle faulting, distributed microfracturing is confined within limited regions of the rock volume, which expedites crack clustering and fault nucleation at low characteristic strains. In ductile faulting, distributed microfracturing occurs more uniformly throughout the rock volume, delaying shear localization to high characteristic strains. Accurate prediction of shear localization requires models that describe crack interactions of the largest flaws that account for crack clustering.

This paper aims to update our understanding of the carbon cycle in the Himalayas, the most intense collisional orogeny globally, by providing new insight into its impact on Cenozoic climate cooling through the use of isotopic variations in both organic and inorganic carbon and an isotopic mass balance model. Our results from 20 selected hot springs show that the relative contributions of dissolved carbon from the mantle, metamorphic decarbonization, aqueous dissolution, and soil organic matter are approximately 2%, 82%, 6%, and 10%, respectively. Approximately 87% ± 5% of CO2 generated in the deep crust precipitates as calcite, while approximately 5.5% ± 1% of this carbon is converted to biomass through microbial chemosynthesis at depths less than 2 km. Our random forests approach yielded a metamorphic carbon flux from the entire Himalayan orogenic belt of approximately 2.7 ∼ 4.5 × 1012 mol/yr. The minor CO2 released into the atmosphere (2.5 ∼ 4.2 × 1011 mol/yr) is comparable to the carbon consumption driven by Himalayan weathering. This paper provides new insights into deep carbon cycling, notably that approximately 93% of deeply sourced carbon is trapped in the shallow crust, rendering orogenic processes carbon neutral and possibly acting as one of the major triggers of long-term climate cooling in the Cenozoic.

The 2018 crisis of Kīlauea volcano stands as a major event in its evolution with a large down-rift effusive eruption that drained a shallow magma reservoir at the summit. The characterization of such active magmatic systems and associated hazardous events remains a necessity and a challenge. The summit area is hydrothermally active and strongly altered as indicated by geological mapping. A unique data set of geophysical measurements was collected around Halemaʻumaʻu crater before its collapse. Magnetic data are interpreted here in combination with geological information, temperature anomalies at the surface, self-potential measurements, and a model of electrical conductivity. 3D forward modeling shows that the main magnetic dipole-like anomaly observed around the crater is not only caused by the crater topography but suggests the presence of an important volume of weakly magnetic material beneath the crater, which may be caused by higher temperature and/or hydrothermal alteration. 3D inversion of the data allows us to explore the first order geometry of the magnetic structures. We complement this inversion with 2D forward modeling in order to refine the geometry of major structures. This study shows the presence of major geological structures in the 2018 collapsed area that may have been associated with mechanical weaknesses and could have played a role in the geometry of the collapse. Therefore, mapping magnetic anomalies and monitoring their temporal evolution are of great interest for constraining the nature and mechanical properties of the underlying formations and their temporal evolution in order to help predict future behavior.

Ultra-low velocity zones (ULVZs) are anomalous structures, generally associated with decreased seismic velocity and sometimes an increase in density, that have been detected in some locations atop the Earth's core-mantle boundary (CMB). A wide range of ULVZ characteristics have been reported by previous studies, leading to many questions regarding their origins. The lowermost mantle beneath Antarctica and surrounding areas is not located near currently active regions of mantle upwelling or downwelling, making it a unique environment in which to study the sources of ULVZs; however, seismic sampling of this portion of the CMB has been sparse. Here, we examine core-reflected PcP waveforms recorded by seismic stations across Antarctica using a double-array stacking technique to further elucidate ULVZ structure beneath the southern hemisphere. Our results show widespread, variable ULVZs, some of which can be robustly modeled with 1-D synthetics; however, others are more complex, which may reflect 2-D or 3-D ULVZ structure and/or ULVZs with internal velocity variability. Our findings are consistent with the concept that ULVZs can be largely explained by variable accumulations of subducted oceanic crust along the CMB. Partial melting of subducted crust and other, hydrous subducted materials may also contribute to ULVZ variability.

Many natural faults are believed to consist of velocity weakening (VW) patches surrounded by velocity strengthening (VS) sections. Numerical studies routinely employ this framework to study earthquake sequences including repeating earthquakes. In this laboratory study, we made a VW asperity, of length L, from a bare Poly(methyl methacrylate) PMMA frictional interface and coated the surrounding interface with Teflon to make VS fault sections. Behavior of this isolated asperity was studied as a function of L (ranging from 100 to 400 mm) and the critical nucleation length, h∗ ${h}^{\ast }$, which is inversely proportional to the applied normal stress (2–16 MPa). Consistent with recent numerical simulations, we observed aseismic slip for L/h∗ $L/{h}^{\ast }$ < 2, periodic slip for 2 < L/h∗ $L/{h}^{\ast }$ < 6, and non-periodic slip for 10 < L/h∗ $L/{h}^{\ast }$. Furthermore, we compared the experiments where L was contained by VS material to standard stick-slip events where L was bounded by free surfaces (i.e., L = the total sample length). The free surface case produced ∼10 times larger slip during stick-slip events compared to the contained fault ruptures, even with identical L/h∗ $L/{h}^{\ast }$. This disparity highlights how standard, complete-rupture stick-slip events differ from contained events expected in nature, due to both the free surface conditions and the heterogeneous normal stress along the fault near the free ends, as confirmed by Digital Image Correlation analysis. This study not only introduces the Teflon coating experimental technique for containing laboratory earthquake ruptures, but also highlights the utility of L/h∗ $L/{h}^{\ast }$ as a predictive parameter for earthquake behavior.

Changes in Earth's magnetic field during the Cretaceous Normal Superchron (CNS) spanning ∼121 Ma to ∼84 Ma hold important clues about the geodynamo evolution. Canonical models predict a persistently strong geomagnetic field with low variability during CNS, which, however, has not been observed in the available absolute paleointensity data and seafloor marine magnetic anomaly (MMA) records. The lack of relative paleointensity (RPI) data across CNS further impedes tests of model predictions. Here, we present a ∼9-Myr (∼94–∼85 Ma) RPI record from a Turonian to Santonian hemipelagic succession from IODP Site U1512 offshore southern Australia. Detailed paleomagnetic and rock magnetic analyses demonstrate that the ratio of natural remanent magnetization (NRM) demagnetized at 20 mT over magnetic susceptibility (MS), that is, NRM20mT/MS, as a reliable proxy for the RPI of the Upper Cretaceous succession. The new RPI record shows marked changes in both intensity and variability at ∼90.8 Ma. Also, the 6 Myr-long (∼94–∼88 Ma), near-continuous, ∼1.2 kyr-resolution RPI record exhibits a strong positive correlation between field intensity and variability. Assuming this correlation holds for the entire CNS, an extrapolated RPI curve for the entire CNS is obtained by integrating the positive correlation with field variability estimates from the MMA data. The extrapolated RPI curve shows a strong and highly variable field in the middle CNS but a weak and stable field at its beginning and ending. These features imply a much more dynamic geodynamo than previously thought, and provide crucial benchmarks for unraveling the geodynamo evolution during CNS.

I employ an elasticity-based method to invert a geodetically derived surface velocity field in the western US using for present-day surface strain rate fields with uncertainties. The method uses distributed body forces in a thin elastic sheet and allows for discontinuities in velocity across creeping faults using the solution for dislocations in a thin elastic plate. I compare the strain rate fields with previously published stress orientations and moment rates from geological slip rate data and previous geodetic studies. Geologic and geodetic moment rates are calculated using slip rate and off-fault strain rates from the 2023 US National Seismic Hazard Model (NSHM) deformation models. I find that computed total geodetic moment rates are higher than NSHM summed moment rates on faults for all regions of the western US except the highest deforming rate regions including the Western Transverse Ranges and the northern and southern San Andreas Fault (SAF) system in California. Computed geodetic moment rates are comparable to the moment rates derived from the geodetically based NSHM deformation models in all regions. I find systematic differences in orientations of maximum horizontal shortening rate and maximum horizontal compressive stress in the Pacific Northwest region and along much of the SAF system. In the Pacific Northwest, the maximum horizontal stress orientations are rotated counterclockwise 40–90° relative to the maximum horizontal strain rate directions. Along the SAF system, the maximum horizontal stresses are rotated systematically 25–40° clockwise (closer to fault normal) relative to the strain rates.

The collisional history between Greater India and the Eurasian plate has been well constrained by the study of exhumed Barrovian metamorphic sequence (BMS) rocks in the Himalayan Range. However, in the southeastern Tibetan Plateau, the collisional records have been obscured by intense, regional-scale strike-slip overprinting and recrystallization. Here, in BMS rocks from the Ailao Shan–Red River shear zone (ARSZ), we report the first discovery of a >250 km long, high-pressure (high-P) granulite belt (>1.0 GPa), identified by the presence of relict kyanite and associated decompression reaction textures. Petrological phase equilibrium modeling showed that exposed micaschists in the region represent exhumed middle crust (20–25 km, 600–670°C), while the high-P granulite rocks are remnants of thickened lower crust (45–55 km, 800–850°C). This indicates that the northeast edge of the ARSZ experienced an additional ∼25 km of uplift and exhumation compared to the southwest side, facilitated by brittle thrusting/imbrication along the Ailao Shan fault (micaschists) and ductile extrusion along the Red River fault (granulite). Geochronological study shows that the upper portion of the BMS preserves older metamorphic ages (52–34 Ma) than the lower portion (32–29 Ma), which was attributed to spatial variation in cooling rates. Using calculated P–T–t–d paths, we also examined variation in density and seismic wave speeds for BMS in the ARSZ. Our data correlate with fieldwork conducted elsewhere within the Himalayan Range indicating that the kyanite to sillimanite transition zone may serve as a “cap” for the horizontal migration of melt within the lower crust.

Elevated pore fluid pressure is proposed to contribute to slow earthquakes along shallow subduction plate boundaries. However, the processes that create high fluid pressure, disequilibrium compaction and dehydration reactions, lead to different effective stress paths in fault rocks. These paths are predicted by granular mechanics frameworks to lead to different strengths and deformation modes, yet granular mechanics do not predict their effects on fault stability. To evaluate the role of fluid overpressure on shallow megathrust strength and slip behavior, we conducted triaxial shear experiments on chlorite and celadonite rich gouge layers. Experiments were conducted at constant temperature (130 and 100°C), confining pressure (130 and 140 MPa), and pore fluid pressures (between 10 and 120 MPa). Fluid overpressure due to disequilibrium compaction was simulated by increasing confining and pore fluid pressure synchronously without exceeding the target effective pressure, whereas overpressure due to dehydration reactions was simulated by first loading the sample to a target isotropic effective pressure and then increasing pore fluid pressure to reduce the effective pressure. We find that the effects of fluid pressure and stress path on the mechanical behavior of the chlorite and celadonite gouges can generally be described using the critical state soil mechanics (CSSM) framework. However, path effects are more pronounced and persist to greater displacements in chlorite because its microstructure is more influenced by stress path. Due to its effects on microstructure, the stress path also imparts greater control on the rate-dependence of chlorite strength, which is not predicted by CSSM.

The Seiland Igneous Province (SIP) is a large province of mafic and ultramafic (UM) complexes interpreted to be relics of a giant plumbing system feeding the Ediacaran Central Iapetus Magmatic Province. The Reinfjord Ultramafic Complex (RUC) is one of the four major ultramafic complexes of the SIP. The RUC has a younger dunite core surrounded by wehrlite and lherzolite embedded in country rocks consisting of layered gabbros with sub-horizontal layering and metamorphosed sedimentary rocks. Here, we develop a 3D subsurface model for the RUC using high-resolution magnetic and gravity data and extensive petrophysical measurements from oriented surface samples and drill core samples. Our model indicates that the RUC narrows in depth, extending a minimum of 1.4 km below sea level, and plunges eastwards below the country rock. This model allows us to decipher the lithologic heterogeneities, and the depth and lateral extent of ultramafic rocks, which we interpret in the context of the geologic history of the area. The RUC is spatially separated from other UM complexes of the SIP and the result of this study indicates a smaller depth extent. Combining these findings with the previously reported distribution of the SIP rocks based on the regional gravity data, we propose that the uplift of the crustal block hosting the RUC is larger than for ultramafic complexes in the northwestern part of the SIP.

We report laboratory experiments and numerical simulations demonstrating that the anisotropic characteristics of rocks play a major role in the elongation of hydraulic fractures (HFs) propagating in a plane perpendicular to the rocks' inherent layering (the bedding planes in sedimentary rocks and foliation planes in metamorphic rocks). Transverse anisotropy leads to larger HF extension in the parallel-to-layers/divider direction compared to the perpendicular-to-layers/arrester direction. This directly promotes vertical containment of HFs in most sedimentary basins worldwide even in the absence of any favorable in-situ stress contrasts or other material heterogeneities. More importantly, the ratio of the energy dissipated in fluid viscous flow in the fracture to the energy dissipated in the creation of new surfaces is found to play a critical role on fracture elongation, with fracture-energy dominated HFs being the most elongated while the viscous dominated ones remain more circular. These results open the door to a better engineering and control of HFs containment at depth in view of the competition between material anisotropy (both elastic stiffnesses and fracture toughness anisotropy) and injection parameters (fluid viscosity and rate of injection).

Genuine non-double-couple (non-DC) components of a seismic source, defined here as the non-DC components that are not due to summation of pure double-couple (DC) components, provide important insight into special physical processes in non-earthquake sources such as explosion, volcano eruption and collapse etc. Yet they remain challenging to be resolved. To address the issue and explore the physical mechanism of those special events, we develop a waveform-polarity-based moment tensor (WPMT) inversion method and employ it to study physical process in the 2014–2015 Bárðarbunga volcano event sequence. The WPMT method incorporates P-wave polarity data and seismic waveforms in the source inversion, designs a source simplicity test to check possible complex rupture in the seismic source, and employs a simulated annealing algorithm to search the best source solution. The simplicity test checks consistency of the source processes in the initiation stage of the event and the major energy release process of the event, thus ensuring that the inferred non-DC components are genuine to the seismic source. Real event and synthetic tests indicate that the WPMT method can identify and resolve genuine non-DC components in a seismic source. The WPMT inversions of the Bárðarbunga sequence yield many genuine non-DC source components and reveal that the eruptions are accompanied by seismic activities in depths of 1–5 km with magma migrations out of chambers, collapses of conduits, failures of normal faults, and a magma recharge at a depth of 9 km accompanied by a failure on a nearby normal fault.