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Southeastern Tibet, which has complex topography and strong tectonic activity, is an important area for studying the subsurface deformation of the Tibetan Plateau. Through the two-station method on 10-year teleseismic Rayleigh wave data from 132 permanent stations in the southeastern Tibetan Plateau, which incorporates ambient noise data, we obtain the interstation phase velocity dispersion data in the period range of 5–150 s. Then, we invert for the shear wave velocity of the crust and upper mantle through the direct 3-D inversion method. We find two low-velocity belts in the mid-lower crust. One belt is mainly in the SongPan-GangZi block and northwestern part of the Chuan-Dian diamond block, whereas the other belt is mainly in the Xiaojiang fault zone and its eastern part, the Yunnan-Guizhou Plateau. The low-velocity belt in the Xiaojiang fault zone is likely caused by plastic deformation or partial melting of felsic rocks due to crustal thickening. Moreover, the significant positive radial anisotropy ( V SH > V SV ) around the Xiaojiang fault zone further enhances the amplitude of low velocity anomaly in our V SV model. This crustal low-velocity zone also extends southward across the Red River fault and farther to northern Vietnam, which may be closely related to heat sources in the upper mantle. The two low-velocity belts are separated by a high-velocity zone near the Anninghe-Zemuhe fault system, which is exactly in the inner and intermediate zones of the Emeishan large igneous province (ELIP). We find an obvious high-velocity body situated in the crust of the inner zone of the ELIP, which may represent maficultramafic material that remained in the crust when the ELIP formed. In the upper mantle, there is a large-scale low-velocity anomaly in the Indochina and South China blocks south of the Red River fault. The low-velocity anomaly gradually extends northward along the Xiaojiang fault zone into the Yangtze Craton as depth increases. Through our velocity model, we think that southeastern Tibet is undergoing three different tectonic modes at the same time: (1) the upper crust is rigid, and as a result, the tectonic mode is mainly rigid block extrusion controlled by large strike-slip faults; (2) the viscoplastic materials in the middle-lower crust, separated by rigid materials related to the ELIP, migrate plastically southward under the control of the regional stress field and fault systems; and (3) the upper mantle south of the Red River fault is mainly controlled by large-scale asthenospheric upwelling and may be closely related to lithospheric delamination and the eastward subduction and retreat of the Indian plate beneath Burma.

Continuous monitoring of blood pressure, an essential measure of health status, typically requires complex, costly, and invasive techniques that can expose patients to risks of complications. Continuous, cuffless, and noninvasive blood pressure monitoring methods that correlate measured pulse wave velocity (PWV) to the blood pressure via the Moens–Korteweg (MK) and Hughes Equations, offer promising alternatives. The MK Equation, however, involves two assumptions that do not hold for human arteries, and the Hughes Equation is empirical, without any theoretical basis. The results presented here establish a relation between the blood pressure P and PWV that does not rely on the Hughes Equation nor on the assumptions used in the MK Equation. This relation degenerates to the MK Equation under extremely low blood pressures, and it accurately captures the results of in vitro experiments using artificial blood vessels at comparatively high pressures. For human arteries, which are well characterized by the Fung hyperelastic model, a simple formula between P and PWV is established within the range of human blood pressures. This formula is validated by literature data as well as by experiments on human subjects, with applicability in the determination of blood pressure from PWV in continuous, cuffless, and noninvasive blood pressure monitoring systems.

Surface wave methods gained in the past decades a primary role in many seismic projects. Specifically, they are often used to retrieve a 1D shear wave velocity model or to estimate the VS,30 at a site. The complexity of the interpretation process and the variety of possible approaches to surface wave analysis make it very hard to set a fixed standard to assure quality and reliability of the results. The present guidelines provide practical information on the acquisition and analysis of surface wave data by giving some basic principles and specific suggestions related to the most common situations. They are primarily targeted to non-expert users approaching surface wave testing, but can be useful to specialists in the field as a general reference. The guidelines are based on the experience gained within the InterPACIFIC project and on the expertise of the participants in acquisition and analysis of surface wave data.

Following the termination of seafloor spreading in the South China Sea (SCS) basin, abundant intraplate volcanism widely spreads in the Indochina block, SCS basin, and Leiqiong area, forming the Southeastern Asian Basalt Province (SABP). The geodynamic origin of the SABP has long been enigmatic and debated. Here, we present a high‐resolution 3‐D upper mantle S‐wave velocity model in the region by conducting earthquake‐based surface wave tomography with seismic data collected across Southeast Asia. The resultant images depict a plume‐like structure beneath the central area of the SABP, characterized by a continuous, sub‐vertical low‐velocity column in the upper mantle. Our new findings, combined with previous geochemical and geodynamic evidence, suggest that the extensive post‐spreading intraplate volcanism within the SABP is likely induced by this focused mantle upwelling, which could be further traced down to the core‐mantle boundary as inferred by existing global velocity models. Plain Language Summary The well‐known Southeastern Asian Basalt Province (SABP), which covers an extensive area of the South China Sea (SCS) and surroundings, is characterized by voluminous volcanism after the cessation of seafloor spreading in the SCS basin. However, the geodynamic mechanism responsible for the formation of the SABP remains debated and not well understood. In this study, we build a high‐resolution 3‐D seismic velocity model in the region utilizing multiple sources of seismic data collected throughout Southeast Asia. We find a distinct plume‐shaped low‐velocity anomaly in the upper mantle beneath the central region of the SABP. Combining with previous geochemical and geodynamic research results, we interpret that the abundant intraplate volcanism within the SABP may be contributed by the underlying focused mantle upwelling. This mantle upwelling, as evidenced in previous global seismic velocity models, could be further traced down to the core‐mantle boundary (∼2,900 km below the Earth's surface). Our tomographic images provide valuable insights into the origin and mantle dynamics related to the young intraplate volcanism that occurred in Southeast Asia. Key Points A high‐resolution 3‐D upper mantle S‐wave velocity model surrounding the South China Sea is constructed A continuous, low‐velocity column is imaged beneath the central region of the Southeastern Asian Basalt Province The post‐spreading intraplate volcanism within the Southeastern Asian Basalt Province is likely induced by the focused mantle upwelling

Mineral systems can be thought of as a combination of several critical elements, including the whole‐lithosphere architecture, favorable geodynamic/tectonic events, and fertility. Because they are driven by processes across various scales, exploration benefits from a scale‐integrated approach. There are open questions regarding the source of ore‐forming fluids, the depth of genesis, and their transportation through the upper crust to discrete emplacement locations. In this study, we investigate an Au–Cu metal belt located at the margin of an Archean‐Paleoproterozoic microcontinent. We explore the geophysical signatures by analyzing three‐dimensional models of the electrical resistivity and shear‐wave velocity throughout the lithosphere. Directly beneath the metal belt, narrow, vertical, finger‐like low‐resistivity features are imaged within the resistive upper‐middle crust and are connected to a large low‐resistivity zone in the lower crust. A broad low‐resistivity zone is imaged in the lithospheric mantle, which is well aligned with a zone of low shear‐wave velocity, examined with a correlation analysis. In the upper‐middle crust, the resistivity signatures give evidence for ancient pathways of fluids, constrained by a structure along a tectonic boundary. In the lower lithosphere, the resistivity and velocity signatures are interpreted to represent a fossil fluid source region. We propose that these signatures were caused by a combination of factors related to refertilization and metasomatism of the lithospheric mantle by long‐lived subduction at the craton margin, possibly including iron enrichment, F‐rich phlogopite, and metallic sulfides. The whole‐lithosphere architecture controls the genesis, evolution, and transport of ore‐forming fluids and thus the development of the mineral system. Plain Language Summary The whole‐lithosphere structure of mineral systems, the link between deep and shallow regions, and the nature, origin, and depth of the source fluids that form mineral deposits are open questions. In this study, we investigate a gold and copper metal belt that is located at the margin of an ancient microcontinent and craton with a history of long‐lived subduction. We explore the region by examining three‐dimensional geophysical images of both the electrical resistivity structure and the shear‐wave velocity structure throughout the lithosphere. Narrow, vertical, fingers of low resistivity in the crust give evidence for ancient pathways of fluids beneath the metal belt. Low velocity and low resistivity signatures in the lower lithosphere are interpreted to represent a fossil fluid source region. We suggest that the geophysical signatures observed were caused by a combination of factors related to mantle metasomatism caused by long‐lived subduction and magmatism. The possible causes include iron enrichment in a more fertile mantle, the presence of F‐rich phlogopite in the lithospheric mantle, and metallic sulfides in the lower lithosphere, including at the base of the crust. The whole‐lithosphere structure and favorable geodynamic/tectonic events control the evolution of ore‐forming fluids that create metal/mineral deposits. Key Points Vertical, finger‐like low‐resistivity zones in the upper crust beneath an Au‐Cu metal belt give evidence for ancient pathways of fluids Low velocity and low resistivity in the lower lithosphere are interpreted to represent a fossil source region for ore‐forming fluids Signatures may be due to a combination of factors: Metallic sulfides, phlogopite, and iron enrichment by refertilization and metasomatism

The local pulse wave velocity (PWV) from large elastic arteries and its pressure-dependent changes within a cardiac cycle are potential biomarkers for cardiovascular risk stratification. However, pulse wave reflections can impair the accuracy of local PWV measurements. We propose a method to measure pressure-dependent variations in local PWV while minimizing the influence of pulse wave reflections. The PWV is computed from the pulse transit time between two forward-traveling pulse waveforms obtained across known path length, after measured/modelled flow-based wave separation analysis (WSA). An in-vivo study of 60 participants (24 female), was conducted to compare inter- and intra-cycle variations in PWV obtained from measured and forward pulse waves. For this, proximal and distal diameter waveforms from the carotid artery, along with carotid tonometry, were recorded using a custom bi-modal arterial probe. The carotid blood flow for WSA was captured with an ultrasound imaging system. The reference PWV was derived from the Bramwell-Hill equation. After WSA, the reliability of PWV measurement improved with coefficient of variation reducing from 25% to 10% near the peak of the pulse waves and matched the reference PWV with no statistically significant difference. The average PWV at foot of the pulse wave before and after WSA were comparable to the reference PWV with no statistically significant difference. The coherence of carotid pulse pressure obtained from the mean values of PWV within a cardiac cycle after WSA with that of the carotid pulse pressure from tonometry, substantiates the results obtained for reflection-free PWV. The reliability of measuring local PWV and its pressure dependent variations within a cardiac cycle is improved by combining transit-time approach with WSA.

Pulse wave velocity (PWV) is the most widely used measurement of arterial stiffness in clinical practice. This study aimed to evaluate and compare the relationships between carotid‐femoral pulse wave velocity (cfPWV) and brachial‐ankle PWV (baPWV) and the presence of carotid plaque. This study was designed cross‐sectionally and included 6027 participants from a community‐based cohort in Beijing. Logistic regression analyses were performed to evaluate and compare the associations of cfPWV and baPWV with the presence of carotid plaque. The mean (SD) cfPWV and baPWV were 8.55 ± 1.83 and 16.79 ± 3.36, respectively. The prevalence of carotid plaque was 45.26% (n = 2728). Both cfPWV (per 1 m/s increase: OR = 1.11, 95% CI: 1.07–1.16) and baPWV (OR = 1.04, 95% CI: 1.02–1.06) were independently associated with carotid plaque after adjusting for various confounders. Compared with bottom quartile (cfPWV ≤7.31 m/s and baPWV ≤14.44 m/s), the top quartile of cfPWV and baPWV had a significantly higher prevalence of carotid plaque (for cfPWV: OR = 1.59, 95% CI: 1.32–1.92; for baPWV: OR = 1.53, 95% CI: 1.26–1.86). However, the relationship of baPWV and carotid plaque was nonlinear, with a positive trend only when baPWV < 16.85 m/s. When comparing relationships between PWV indices and carotid plaque in one model, both cfPWV and baPWV were significantly associated with carotid plaque in participants with baPWV < 16.85 m/s; however, only cfPWV was independently associated with carotid plaque in participants with baPWV ≥16.85 m/s. Both cfPWV and baPWV were significantly associated with carotid plaque in the Chinese community‐based population. Furthermore, cfPWV was more strongly correlated with carotid plaque than baPWV in participants with baseline baPWV ≥16.85 m/s.

Seismological observations in the lunar mantle, in conjunction with experimental knowledge on the elastic wave velocities and density of lunar mantle minerals, provide important constraints on the composition and mineralogy of the lunar mantle. Here we report elastic wave velocities and density of a lunar orthopyroxene (Mg0.84Fe0.13Ca0.03SiO3) up to 5.5 GPa and 1,273 K. The result shows that the bulk and shear moduli of orthopyroxene decrease with increasing iron content. Based on the mineral elasticity data, we modeled the P‐ and S‐wave velocities and density of petrologically suggested lunar upper mantle rock composition. The petrological lunar upper mantle rock model shows consistent seismic wave velocities with those observed in the lunar upper mantle whereas markedly lower density. Our modeling suggests an iron‐rich (Fe/(Mg + Fe) = 0.20) lunar upper mantle to explain P‐ and S‐wave velocities and density of the lunar upper mantle at 40–740 km depth.

The Himalayas is currently rising due to the collision of the Indian and Asian plates and hosts frequent earthquakes, some of which are devastating, such as the 2015 Mw7.8 Gorkha earthquake. Despite the importance of deep dynamic processes to understand the uplift of the Himalayas and the occurrence of large earthquakes, it remains limitedly constrained due to the lack of a detailed three‐dimensional subsurface image under this region. Here, we construct new models of shear‐wave velocity and radial anisotropy down to the 150 km depth from Rayleigh‐ and Love‐wave tomography in the Nepal Himalayas. We find that the 2015 Gorkha earthquake and its main aftershock occurred in a velocity contrast that is presumably interpreted as Main Himalayan Thrust (MHT). A duplex structure, imaged as relatively high velocities, is inferred to exist above MHT under the Lesser Himalayas. This duplex shows heterogeneous features along the strike of the Himalayas that may control the rupture behavior during the occurrence of a large earthquake. Additionally, a low‐velocity anomaly is observed at depths from Moho to 100 km under the Lhasa Terrane and north of the Himalayan Terrane between 85° and 88°E. We interpret this low‐velocity anomaly to be likely caused by mantle upwelling resulting from either possible Indian slab tearing, or northward subduction of the Indian plate. If this is the case, the north‐south trending rifts that situate within the dispersal of the low‐velocity anomaly are probably associated with the mantle upwelling. This study provides a new independent constraint on the geometry of the MHT system and deep dynamic processes occurring in the Nepal Himalaya. Plain Language Summary The 2015 Mw7.8 Gorkha (Nepal) earthquake caused great damages to property and lives. It is widely suggested that the motion of a megathrust (i.e, the Main Himalayan Thrust (MHT) is responsible for the large earthquake. In order to understand the geometry of this thrust system and associated deep dynamics, in this study we constructed a three‐dimensional subsurface image of the Nepal Himalayas using surface wave that travels at the surface of the Earth. Our seismic image, together with previous studies of coseismic slip distribution, reveals that rupture behavior of the 2015 Gorkha earthquake and its main aftershock is controlled by the heterogeneous duplex structure (i.e., a system of imbricate thrust faults) of the megathrust. Additionally, we offer seismic velocity evidence for the occurrence of asthenospheric upwelling beneath the north of the Himalayan Terrane between 85° and 88°E that is likely linked with the variable MHT geometry along the strike of the Himalayas and surface exposed north‐south trending rifts. This study provides a new independent constraint on the geometry of the MHT system and deep dynamic processes occurring in the Nepal Himalayas. Key Points New lithospheric‐scale shear‐wave velocity and radial anisotropy models are constructed using surface‐wave tomography A duplex structure of Main Himalayan Thrust is imaged as relatively high velocities under the Lesser Himalayas, controlling earthquake rupture propagation Mantle upwelling is inferred to occur beneath north of the Himalayan Terrane between 85° and 88°E

This paper considers the uncertainty in the shear wave velocity (Vs) of soil and rock profiles for use in earthquake site response calculations. This uncertainty is an important contributor to uncertainty in site response, which in turn is an important contributor to uncertainty in earthquake ground motions and in seismic hazard. The paper begins with a discussion of the different types of uncertainty and how they are characterized in probabilistic seismic hazard analysis, and how this differentiation is particularly ambiguous in the case of soil properties. This is followed by a description of the probabilistic models of Vs that are most commonly used in engineering practice, for both generic and site-specific applications. In site-specific applications, the uncertainty in Vs (which is measured by the logarithmic standard deviation or by the coefficient of variation of Vs) is lower than in generic applications, but other elements of the profile model are also different. Next, the paper discusses the issues that arise in characterizing the uncertainty in Vs in site-specific applications using non-invasive surface wave methods and summarizes the insights obtained by comparing the results from multiple blind studies in which the same surface-wave data (and no other site-specific data) were provided to multiple teams of analysts. Finally, the paper provides recommendations on how to characterize uncertainty in Vs for both generic and site-specific applications.