The Weihe Basin in central China hosts an invaluable sedimentary archive documenting long-term interactions between hydroclimatic fluctuations and soil erosion dynamics. However, quantitative reconstructions of erosion intensity variations and their phased coupling with monsoon oscillations remain relatively limited. X-ray Fluorescence (XRF) provides a fast, non-destructive, and high-resolution elemental analysis, yet its semi-quantitative elemental data pose challenges for direct comparison with other environmental proxies. To address this, we integrated calibrated elemental log-ratios and sedimentary-geophysical evidence to reconstruct late Middle Pleistocene climate evolution and soil erosion in the Weihe Basin over the past 226 ka. Our results identify six distinct erosion stages that generally coincide with major climatic transition phases. The climate alternated between warm-humid and cold-dry conditions, accompanied by a shift in the depositional environment shifted from floodplain to aeolian-dominated settings. Elemental ratios and gamma-ray (GR) logs serve as robust proxies for hydrodynamic intensity and grain-size variations, although ln(Rb/Sr) exhibits certain limitations as a weathering indicator in this context. Furthermore, sedimentary evidence indicates that major soil erosion events are phase-locked with critical climatic transitions (e.g.,198-185 ka, 181-170 ka, similar to 160 ka, similar to 120 ka, 72 ka and 25 ka), including suborbital millennial-scale abrupt monsoon events. This study confirms that hydroclimatic instability driven by rapid East Asian Summer Monsoon (EASM) oscillations represents the primary forcing mechanism for regional denudation. The synergy between sparse paleovegetation and extreme hydrological events significantly amplified surface erodibility susceptibility, providing a mechanistic link between millennial-scale climate shifts and accelerated geomorphic remodeling. Moreover, erosional and depositional processes in the Weihe Basin are primarily driven by EASM variability against the backdrop of global ice volume fluctuations. Ultimately, these findings highlight the sensitivity of inland monsoon-margin catchments to global climatic oscillations and establish a process-based framework for understanding soil erosion responses under future climate change.

The Asian monsoon is crucial for sustaining billions of people, yet its geological history, primary drivers, and mechanisms remain contentious. To explore the potential driving mechanisms of East Asian summer monsoon (EASM) precipitation since the Early Pleistocene, we here present data from a 272-m-long core of Quaternary lacustrine-fluvial-aeolian sediments from the Weihe Basin in central China. The chronology of the core is established through magnetostratigraphy and tie-point matching with speleothem oxygen isotope (delta 18O) curves. Lithofacies and geochemical profiles reveal that the core records a sedimentary succession from lacustrine through fluvial to aeolian depositional environments since 1.18 Ma. End-member (EM) modeling of lacustrine deposits shows that the transport and deposition of coarse EM3, EM4, and EM5 components are linked to vigorous nearshore hydrodynamics. Consequently, the summed proportion of these three EMs serves as an indicator of monsoon-induced paleolake transgressions and regressions. Reduced precipitation causes lake contraction, and the development of littoral lake sub-facies enriched in coarse EM components. Hydrodynamic sorting, modulated by catchment hydrology, imparted a precession signal to lacustrine bulk-sediment XRF element intensities. On orbital timescales, EASM precipitation variations are governed by precession-dominated boreal-summer insolation. Featuring a robust chronology and sensitive response of lacustrine proxies to precipitation, our findings confirm that insolation forcing fundamentally governs precipitation patterns in East Asia.

The Changbaishan volcano (CBSV) complex is the largest and most active intracontinental volcanic system in Northeast Asia and comprises multiple active edifices. Although these volcanoes are associated with asthenospheric upwelling induced by Pacific Plate subduction, they exhibit pronounced differences in magma composition and eruptive behavior. Here, a high-resolution crust-to-mantle three-dimensional (3D) electrical resistivity model of CBSV is presented, developed from densely sampled Magnetotelluric (MT) surveys and 3D inversion. The resulting model delineates a trans-lithospheric magmatic network and a dynamic plumbing architecture, consistent with an evolutionary paradigm characterized by "deep-source homology and shallow differentiation" across the volcanic field. Joint interpretation of electrical structures together with seismicity and geodetic deformation indicates ongoing magma recharge beneath the volcanic field. These results provide a robust basis for volcanic hazard assessment at CBSV and offer practical constraints for monitoring strategies. More broadly, a conceptual framework is proposed to account for the diversity of intracontinental eruption styles far from plate boundaries, in which fault architecture and topographic loading exert primary control on magma transport pathways and eruption dynamics. Overall, this work shifts the interpretation of intracontinental volcanism from a "magma-composition-centered" view toward a "tectonic-melt coupling" framework, with implications for volcanic systems worldwide. (c) 2026 China University of Geosciences (Beijing) and Peking University. Published by Elsevier B.V. on behalf of China University of Geosciences (Beijing). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

This study investigates the transient deformation signals associated with the Ludian M6.8 earthquake, which occurred on June 22, 2014, in southwestern China, using Global Navigation Satellite System (GNSS) data. Within the framework of the Kalman filter, the study employs a First-Order Gauss-Markov (FOGM) model to construct and isolate transient deformation signals, extracting the FOGM time series. Principal Component Analysis (PCA) is then applied to decompose the extracted time series and analyze the spatiotemporal evolution of the top two Principal Components (PCs) of the East-West (EW) and North-South (NS) components, revealing their correlation with the Ludian earthquake. Furthermore, a quantitative analysis of the spatial response characteristics of the second Principal Component (PC2) of the EW component and the first Principal Component (PC1) of the NS component is conducted to characterize the spatial evolution pattern of transient deformation. Finally, the spatial distribution of transient deformation signals is compared with the known co-seismic rupture characteristics, providing further evidence that the extracted signals represent real post-seismic deformation rather than noise. The key findings of this study are as follows: 1. The PC2 of the EW component and the PC1 of the NS component primarily represent post-seismic transient deformation signals associated with the Ludian earthquake. The post-seismic deformation evolution exhibits two distinct phases: a sustained deformation phase from the earthquake occurrence to early 2016 and a recovery phase starting from early 2016, reflecting the time-dependent characteristics of the post-seismic relaxation process. 2. In addition to the well-known linear trend and periodic components, the GNSS displacement time series may also contain non-linear periodic components, suggesting that GNSS data are influenced by a combination of crustal dynamics, surface environmental changes, and anthropogenic factors. 3. The integration of Kalman filtering and PCA-based dimensionality reduction analysis effectively isolates transient deformation signals and nonlinear periodic signals from complex background noise, enhancing the interpretability of GNSS data. This approach provides a highly efficient data processing method for analyzing earthquake-induced deformation.

The accuracy of seismic sensor orientation is not only one of the crucial indicators for measuring the quality of observational data but also the data basis for seismological methods such as receiver functions, shear wave splitting, and full waveform tomography. This study focuses on 949 broadband seismic stations in Chinese mainland, utilizing 1890 teleseismic events with magnitudes greater than 6 and epicentral distances ranging from 30 degrees to 90 degrees. By calculating the minimum P-wave energy on the tangential component, we derive the actual back azimuth and subsequently estimate the misorientation of the sensors. For the first time, a comprehensive database spanning from August 2007 to December 2023 has been systematically established to document sensor misorientation. The research results show that 576 stations consistently maintained misorientation within 10 degrees, demonstrating good stability. There are 373 stations that experienced at least one period where the misorientation exceeded 10 degrees, accounting for 39% of the total number of stations. As of December 2023, 8% of the stations still exhibit misorientation exceeding 10 degrees. Through waveform comparisons of nearby earthquakes recorded by co-located seismometers and strong-motion seismometers, sensors with misorientations above 10 degrees can be reliably identified. Further analysis reveals that stations with larger error values are mainly distributed in western China, which may be related to the dipping interfaces and relatively strong anisotropy of the underlying medium, though errors generated by the seismometers themselves cannot be ruled out. By testing the receiver functions of stations with different levels of misorientation in the database, we have gained a deeper understanding of the importance of precise correction of the station azimuth. The sensor misorientation database of stations in Chinese mainland constructed in this study comprehensively evaluates the orientation of seismometers, details the temporal variation of sensor misorientation for individual stations, and provides a more intuitive and accurate reflection of the operational status of the stations as well as reliable data support for scientific researchers.

The Yitong Volcanic Area (YVA) in Jilin Province is a relatively rare "compression type" volcanic system worldwide. Its formation mechanism and eruption mode have unique features. The Yilan-Yitong Fault (YYF) runs through this volcanic rock belt and has demonstrated prominent segmented fracture characteristics since the Quaternary Period. The paleoseismic activity of the Yitong Fault Zone (YFZ) is different from that of other fault zones within this area. This study aimed to investigate the deep magma system in the YVA and its influence on the segmented activities of YYF. Magnetotelluric (MT) measurements were performed in the YVA. A total of 87 MT sites were arranged in the area. A high-resolution three-dimensional (3D) electrical structure model of the lithospheric scale from the crust to the upper mantle in the study area was established with the 3D inversion method. This model suggests that the shallow section of the upper crust of the YVA and the northwestern part of the Songliao Basin were mainly low-resistivity zones, which corresponded to the widely distributed sedimentary layers in this area. The middle and lower crust in the study area was primarily a complete high-resistivity body. A large-scale magmatic system began to appear at a depth of 25 km in the YVA. This magmatic system continued to extend downward, exceeding 70 km. The magma chamber in the YVA was in contact with the YYF in the lower crust. The YYF was the dominant material surging upward through the magma channel. Additionally, deep magmatic activities exerted a crucial influence on the seismic rupture segmentation characteristics along the YYF and the uplift mechanism of the Yitong Basin. The results of this study provide crucial geophysical constraints for depicting the fine depth structure of the YVA while enlightening the investigation of the rupture propagation mechanism within the volcanic terrain fault zone.

The long-term seismicity inferred from the physics-based simulations provide a valuable complement to limited historical and instrumental records, especially in continental interiors characterized by low-frequency strong earthquake activity. This study presents a detailed long-term (steady-state) slip rate model for major active faults in the northern Shanxi rift, constrained by multi-source geophysical kinematics and inverted using NeoKinema program package. Utilizing our derived fault kinematic model as input for the physics-based seismicity simulator (Virtual Quake, VQ), we simulated the fault-scale long-term seismicity. Our results reveal that the northern Shanxi rift is dominated by horizontal crustal extension with a maximum extension rate of approximately 1 mm/year in the NW direction and associated normal faulting. Active boundary faults trending NEE exhibit relatively high slip rates, ranging from approximately 0.30–0.74 mm/year. In contrast, secondary or buried faults with nearly EW trending orientations generally have lower slip rates, fluctuating around 0.2 mm/year. Notably, the nearly NS-trending faults in the southern region exhibit a significant right-lateral strike-slip motion (~ 0.4 mm/year), while the NW-trending fault zones in the northern region are characterized by predominantly left-lateral strike-slip motion (~ 0.3 mm/year). Statistical analysis of the Coefficient of Variation (CoV) of recurrence intervals in the simulated long-term seismicity indicates that the recurrence intervals of most faults are relatively uniform, except for the east segment of the North Liulengshan fault. The high CoV value for this fault suggests a more pronounced tendency for seismicity clustering. In contrast, the North Hengshan fault exhibits the lowest CoV value, indicating relatively stable seismicity and a quasi-periodic pattern. Correlation analysis between fault slip rates and recurrence interval variability reveals that faults with lower slip rates tend to exhibit stronger clustering behavior, while faults with higher slip rates tend to exhibit a more pronounced quasi-periodic pattern. Seismic hazard analysis based on the conditional probability of strong earthquakes further highlights the significant seismic potential of the North Hengshan fault. The estimated probabilities of strong earthquakes(> M6.5) occurring within the next 100 and 200 years are80% and 96%, respectively, indicating its significant strong earthquake potential in the North Hengshan Fault. Graphical Abstract

The 2018 Kilauea eruption has been extensively studied to unravel its complex dynamics. Monitoring velocity changes around the volcano over time and depth is crucial for distinguishing magma behavior from other factors. By analyzing ambient noise sources in Hawaii, we employed surface wave interferometry to measure average time-frequency velocity changes of the medium related to the 2018 Kilauea eruption, using volcanic tremor (1–3 s) for pre-eruption changes and oceanic noise (3–5 s) for changes after the eruption onset. Depth-dependent relative shear velocity changes were obtained using a weighted-damped least squares inversion. The results showed a clear positive velocity change with an average amplitude of + 1.3

Long-term earthquake catalogs can offer valuable constraints for investigating fault geometry and locking patterns at depth, which are crucial for assessing seismic hazard. However, there is still a scarcity of long-term, high-precision earthquake catalogs for the Anninghe–Daliangshan–Zemuhe Fault (ADZF). Based on the abundant phase data from Xichang dense seismic array and the China Earthquake Networks Center, we precisely relocated approximately 17,000 events using the double-difference relocation method, constructing an updated earthquake catalog for the ADZF. Our results reveal the complex structure of the ADZF, providing the detailed information of the dip angle and dip direction of different fault segments. The seismogenic layer depth of the Anninghe Fault is constrained to be less than 15 km, whereas the Daliangshan Fault had a notably deeper seismogenic layer, ranging from roughly 20 to 30 km in depth. Two significant locked segments were identified on the Anninghe–Zemuhe Fault: one in the Shimian–Mianning segment and another in the Mianning–Puge segment. Beneath Mianning, a zone of significant seismic activity extended from shallow depths down to approximately 10 km, separating the two locked segments. If the two segments ruptured independently, the possible maximum magnitudes for the Shimian–Mianning and Mianning–Puge segments should be Mw 7.1 ± 0.2 and Mw 7.3 ± 0.2, respectively. For the Shimian–Mianning segment, the fault locking pattern exhibited shallow locking and deep creeping, with the locking depth gradually increasing from north to south and showing heterogeneity along the fault strike. Overall, this study not only enhanced the precision of earthquake relocations, but also filled the gap in long-term seismic records of the region, offering insights into fault geometry, seismogenic layer depth, and locking distribution.

The accuracy of absolute timing in seismic records is critical for applications such as earthquake location, seismic tomography, and earthquake early warning. This study develops and applies a high-precision method for detecting clock errors based on continuous three-component waveform data recorded from 2019 to 2023 at 188 permanent seismic stations in and around the Ordos block. The method combines multicomponent ambient noise cross correlation and weighted stacking to estimate daily clock errors by analyzing the symmetry deviation of cross-correlation functions. Constraining each station’s drift estimate with multiple neighboring pairs through weighted averaging improves the stability and robustness of the detection, making it well suited for monitoring of large-scale seismic networks. The results show that: (1) A total of 72 stations (38.3%) exhibited significant clock drift over the 5-year period, with an average annual anomaly rate of ∼11.6%; some stations experienced clock drift for over 10 months in a single year. (2) The maximum drift exceeded ±10 s, whereas drifts larger than ∼0.5 s can be detected and validated, typically using teleseismic events. The anomalous stations were spatially dispersed, indicating that the drift was primarily caused by station-specific issues rather than regional environmental interference. (3) The types of clock drift observed include linear, nonlinear, abrupt, and compound patterns, reflecting a range of instrumental failures or environmental factors. In addition, validation using an adjacent-teleseism double-differential timing method successfully identified a subtle drift of ∼0.2 s at station SX.LOF, demonstrating the method’s potential sub-second sensitivity, though such detections near the threshold are less stable. This study establishes a 5-year database of clock errors for seismic stations in the Ordos region, providing essential data support for seismological applications and offering a methodological reference for quality control in large seismic networks.

The Ordos block is a rigid portion of the North China Craton lying within the India-Eurasia collision zone that experiences little internal deformation, but is surrounded by active faulting, extensional grabens, and seismicity. In the surrounding region, geodetic studies have imaged complex crustal deformation, while seismic studies have suggested that the lithosphere is encountering regional modification by mantle convection. The Ordos block thus presents a valuable opportunity to compare seismic and geodetic constraints and investigate geodynamic processes affecting the region’s lithosphere. We here robustly image vertical land motion and horizontal strain rates using observations from the geographically extensive Global Navigation Satellite System and leveling networks in and around the Ordos block. Our results indicate that the Ordos block uplifts with some lateral variability at 0.5−2.0 mm/yr. In the northeastern Ordos block and Datong volcanic area, the crustal uplift rates are 2.0−4.0 mm/yr on average, much faster than those elsewhere on the block. We correct for non-tectonic vertical motion from surface hydrological loading and glacial isostatic adjustment, finding that these do not explain the vertical rate anomalies. Horizontal crustal extension and uplift are accompanied by a pattern of crustal contraction at the Datong volcanic field. Additionally, we find uplift west of and subsidence east of the Qinling Orogenic Belt, which are inconsistent with eastward crustal extrusion along it, suggesting instead a negligible migration of crustal materials especially to the east of 106°E. Comparing the geodetic measurements to evidence from seismic velocity anomalies and numerical simulation, we argue that the motions are consistent with lithospheric re-equilibration resulting from the heterogeneous thinning of the lithosphere by convective mantle upwelling and radial flow as well as shortening from the India-Eurasia collision.

The intraplate volcanic activity refers to the volcanic activity that occurs within the continent far from the boundary of plate tectonics. The Longgang volcano located in northeastern China is a natural experimental area for studying intraplate volcanic activity. We conducted continuous magnetotelluric surveys in the Longgang volcanic area and its surrounding areas in Jilin Province in 2020 and 2022, respectively and obtained 141 broadband measurement sites that covered the Longgang volcanic area. Through 3D inversion, we obtained a detailed 3D electrical structure model of the crust and upper mantle in the area. This model reveals that the crust in the Longgang volcanic area and its surrounding areas are a high-resistivity body, representing the volcanic rocks generated by the large-scale eruption and condensation during the early magmatic activity in the volcanic area. There are multiple magma channels beneath the Longgang volcanic area that merge and continue to extend downwards at the upper mantle scale through the Moho. These magma channels may have dominated recent volcanic eruptions, crustal uplift, and small earthquake activity. This model clearly shows the formation mechanism of a continental intraplate volcanic system across the lithosphere from the mantle source to the surface. Combined with petrology and geochemical data, it is speculated that the magma system in the Longgang volcanic area may rise rapidly from the asthenosphere mantle to the decompression melting in the crust, leading to eruption. These results can not only provide a deep geophysical basis for predicting the risk of eruption in the Longgang volcanic area but also inspire an understanding of the formation mechanism of intraplate volcanoes.

Active faults that develop in urban regions pose significant seismic hazards to cities with densely concentrated populations and wealth, as demonstrated by several destructive earthquake events in the recent decades. Lintong -Chang 'an fault is a known active fault, which comprises multiple branches and traverses the urban area of Xi 'an in Weihe Graben -a prominent Chinese megacity with a rich 3000-year-old civilization and a population of 13 million. High-resolution seismic reflection profiles and borehole transects, combined with Quaternary strata dating, reveal that: (1) to the south of Shenhe Loess Tableland, two northern branches of the fault zone follow the trend of the middle part and extend to the front of the Qinling mountains in the SW240 degrees direction; (2) the strata since the late Middle Pleistocene on the borehole transect have been offset, with the vertical displacement of the-216 ka layer measured at 5.9 +/- 0.3 m, the-118 ka layer at 3.8 +/- 0.3 m, and 41 ka layer at 1.0 +/- 0.1 m, indicating an average vertical slip rate of 0.02 -0.04 mm/yr for the individual branch at the study site. Notably, the slip rate of the entire fault zone could be two to three times that of a single branch. Despite the relatively low-slip rate, the fault traverses the megacity of Xi 'an, is situated in the relay zone of two large, strongly active basin boundary normal faults (Huashan and Qinling Piedmont faults) and is responsible for the formation of Xi 'an ground fissures. Hence, it is necessary to pay special attention to this fault.

Longgang Volcano (LGV) and Changbaishan Tianchi Volcano (CTV) share a common magmatic source at mantle depths. However, the two volcanoes have produced completely different types of eruptions. By performing 3D inversion of an MT dataset that completely covers the LGV and CTV, we have obtained high-resolution electrical resistivity images. The results reveal that the two volcanoes have distinct magmatic plumbing systems, and this is likely the reason for their different eruptive styles. Results from 3D modeling do not show a magma chamber in the shallow crust beneath LGV, interpreted as the rapid rise of the magma from the mantle is responsible for producing a series of densely distributed volcanic cones in the LGV field. In contrast, there is a magma chamber in the upper crust beneath the CTV, where the fractional crystallization and mixing of magma has occurred. This magma chamber has facilitated multiple centralized eruptions, and thereby has led to the formation of the large CTV volcanic cone. These results indicate that differences in their crustal structures may have controlled the different eruptive activities of the LGV and CTV in CVS, Northeast China.

SUMMARY The northwestern margin of the Ordos block is structurally separated by the Yinchuan–Hetao graben system. As one of the most active intracontinental graben systems within the Eurasian continent, its kinematic pattern of crustal extension is crucial for unraveling the ongoing processes of intracontinental graben formation, while it remains unclear principally due to a lack of geological constraints on crustal deformation. We obtained and analysed a densified GNSS (Global Navigation Satellite System) velocity field in this region. Our results suggest that the western margin of the Hetao graben exhibits the NW-directed crustal extension (∼ 1.1 mm yr−1), which can be attributed to the conjugate transtension resulting from the left-lateral motion along the E–W-trending northern boundaries of the Alashan and Ordos blocks, as well as the right-lateral motion along the N–S-trending western margin of the Ordos block. Additionally, in response to the NE-directed extrusion of the Tibetan Plateau, the Alashan block undergoes approximately NE-directed contraction (4.9 ± 1.1 nanostrain yr−1) and NW-directed extrusion (2.8 ± 0.8 nanostrain yr−1), which vacates space for the crustal extension of the Yinchuan graben with a rate of 0.9 ± 0.1 mm yr−1. Although it is challenging to determine whether the left-lateral motion (approximately 1 mm yr−1) along the E–W-trending Hetao graben is the far-field effect of western Pacific subduction, the gradual decrease in right-lateral motion from the N–S-trending western margin of the Ordos block toward the north side of the Yinshan Orogen manifests the far-field effect of the Indo-Eurasian plate convergence extending into the Mongolian Plateau.

Located at the forefront of the collision between the Indian and Eurasian Plates, the Tibetan Plateau experiences intense crustal movement. Traditional ground-based geodetic monitoring, such as GNSS and leveling, is challenging, due to factors such as high altitude and harsh climate, making it difficult to accurately determine a high-resolution crustal deformation field of the plateau. Unaffected by ground observation conditions, InSAR technique has key advantages for obtaining extensive and high-resolution crustal deformation fields. This makes it indispensable for crustal deformation monitoring on the Tibetan Plateau. This study used Sentinel-1 data from 2014 to 2020 to compute the ascending and descending InSAR deformation fields for the Tibetan Plateau. This was conducted with a measurement accuracy of approximately 3 mm/yr. Building upon this, we integrated InSAR and GNSS data to yield kilometer-resolution three-dimensional (3D) crustal deformation and strain rate fields for the Tibetan Plateau. A spherical wavelet analysis was used to decompose the 3D deformation field and separate the non-tectonic crustal deformation to increase the strength of the tectonic deformation signal. Short-wavelength (<110 km) deformations match the distribution of fault movement, post-seismic deformations, and other non-tectonic factors. Long wavelength (>110 km) deformation mainly results from subsidence in the central plateau and uplifts along the Himalayan Arc. This indicates that the Tibetan Plateau may have stopped the entire uplift and entered a local collapse stage. Furthermore, the deformation fields at different spatial scales reveal that the plateau exhibits discontinuous deformation in short wavelengths and continuous deformation in long wavelengths. The findings of this study contribute to resolving the controversy between the Block and Continuum Deformation models of the Tibetan Plateau.

SUMMARYThe Daliang Shan is a tectonic unit that connects the active southeastern Tibetan Plateau with the stable South China block. As a newly generated (formed later than the Xianshuihe–Xiaojiang active fault system) seismotectonic zone induced by the Tibetan tectonics, the detailed constraints of the crustal deformation are central to the understanding of the kinematics and dynamics of the Tibetan expansion. This paper establishes and analyses a high-spatial resolution global positioning system (GPS) velocity field from a dense GPS network in this region. Our modelling results indicate that, in contrast to the equivalent sinistral strike-slip rate of approximately 5 mm yr–1 on the Anninghe–Zemuhe and Daliangshan faults, their inferred interseismic locking depth varies within a large range. The southern segment of the Anninghe Fault and the middle segment of the Daliangshan Fault have deep locking depths of ∼13 km, indicating that the seismic risk is high in these areas. In addition, the detectable counter-clockwise rotation rate of 0.35 ± 0.12° Myr–1 of the Mabian block makes a significant contribution of ∼50 per cent to the strike-slip motion on its boundary faults. This counter-clockwise rotation may be induced by a left-lateral shear gradient with southeastward motion relative to the South China-fixed reference frame, indicating the significance of a simple-shear pattern in exploring the kinematics of the encroachment of the Tibetan tectonics upon a stable block (craton).

The North China Craton is a stable cratonic block that emerged in the Paleozoic era. During the late Mesozoic era, lithospheric stretching and thinning, as well as volcanic activities, caused extensive destruction of the craton. In this study, we conducted a magnetotelluric profile within the North China Craton, covering the western (Ordos Block), middle (Taihangshan Uplift), and eastern (North China Plain) segments of the craton. The electrical structure along the profile was obtained. Our analysis revealed that the Huoshan fault and the piedmont fault of the Taihangshan are large-scale high- and low-resistivity boundaries, which traverse the entire crust. These two faults divide the three major secondary blocks within the North China Craton. The crust of the Taihangshan Uplift is characterized by a layered high-resistivity body, while the lower and middle crust exhibits widespread high conductivity layer. The crustal-scale structures of the North China Plain and the Ordos Block on both sides are dominated by stable layered resistivity structures. This indicates that the lithospheric destruction near the profile may have mainly concentrated beneath the central Taihangshan Uplift. The seismogenic environment of the 1303 Hongtong earthquake may have been controlled by multiple factors. The upwelling of mantle-derived materials in the lower and middle crust beneath the Taihangshan Uplift caused the extension of the Shanxi Graben fault system where the Linfen Graben is located. The main controlling factor of this earthquake is the southeastward sliding of the Huoshan fault. We speculate that the destruction process beneath the central Taihangshan Uplift of the North China Craton exhibited a bottom-up process, and the thermo-mechanical-chemical erosion mechanism may have dominated the destruction of craton.

Transient deformation, such as post-seismic slip, slow slip and pre-seismic slip events, is a limited low-frequency deformation that can last for hours to months, in contrast to a sudden slip on a fault caused by earthquakes. Continuous Global Positioning System (CGPS), one of the most common geodetic techniques for continuously monitoring crustal deformation, is capable of capturing transient deformation signals. A critical point in characterizing transient deformation signals is the development of extracting and deciphering transient deformation signals from a huge and messy data set of position time series. Principal Component Analysis (PCA), one of the data-driven methods, has been employed to derive transient deformation signals from position time series combing with Kalman filtering. Independent Component Analysis (ICA) performs well in recovering and separating the sources of observed data, however, it is rarely used in extracting transient deformation signals. We aim to decompose the transient deformation signals from the daily GPS observation deployed in Akutan Island from 2007 to 2015 with the ICA method and obtain the spatiotemporal responses to the source signals of transient deformation. Our results indicate that ICA method can also characterize effectively transient deformation signals spatially and temporally. Additionally, the independent relationship between sources obtained by ICA allows for flexibility in linearly combining different sources.