Journal of Geodynamics最新文献

{"title":"Crustal stress pattern at Mt. Etna volcano","authors":"Salvatore Scudero","doi":"10.1016/j.jog.2023.102017","DOIUrl":"10.1016/j.jog.2023.102017","url":null,"abstract":"<div><p>Stress fields may exhibit variegated patterns, especially in volcanic areas where several processes superimpose their effects in space and time. The comprehension of such patterns may not be straightforward to investigate. This work investigates the pattern of the crustal stress<span> in the area of Mt. Etna Volcano (Sicily, Italy). This has been possible through a collection of more than 800 stress indicators derived from seismological and volcanological/geological information. In particular, the type of collected data allows to consider, for the first time in this area, two different temporal steps in the evolution of Etna volcano: the present-day and the previous volcanic phase at 15 ka. Results indicate a transition between a background shallow NW-SE tensional regime and a deep SW-NE compressional one that occurs between 6 and 16 km depth and which well fits with the present-day geodynamic framework of the area. The occurrence of small-scale lateral variations is interpreted as the second-order effect of the structures of the active front buried beneath the volcano, to the volcano loading, and to the feeding system. The temporal variations in the area surrounding the volcano suggest a major rearrangement of the background stress field evidenced by the swap between minimum and maximum horizontal stress directions. Conversely, during the same period, the stress pattern in the exact correspondence of the volcanic edifice showed to be stable and with a radial arrangement. Such coherence would support the literature which suggests a long-term inflation process started at least 15 kyr ago.</span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"159 ","pages":"Article 102017"},"PeriodicalIF":2.3,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139068816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation mechanism of carbonaceous materials in fault gouge of Wenchuan earthquake","authors":"Deyang Shi ,&nbsp;Yaowei Liu ,&nbsp;Jin Shi","doi":"10.1016/j.jog.2023.102016","DOIUrl":"10.1016/j.jog.2023.102016","url":null,"abstract":"<div><p>Carbonaceous materials<span> are widely present in the seismic fault zone. They play a crucial role in lubricating the fault slipping. To date, the formation mechanism of carbonaceous materials is still unclear. In this work, we have conducted a carbon dioxide hydrogenation reaction experiment in a homemade high temperature reactor for the purpose to insight the formation mechanism of carbonaceous materials, with fault gouge used as the catalyst. During the reaction process, carbonaceous materials are formed on the fault gouge, suggesting that the carbonaceous materials in the fault zone are possibly generated from carbon dioxide hydrogenation reaction. These results are important for understanding fault behavior and earthquake physics.</span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"159 ","pages":"Article 102016"},"PeriodicalIF":2.3,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139015050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations of the effective elastic thickness evidence for a wide diffusive boundary between the North American and Eurasian plates in Siberia","authors":"M.K. Kaban ,&nbsp;B. Chen ,&nbsp;R.V. Sidorov ,&nbsp;A.G. Petrunin","doi":"10.1016/j.jog.2023.102015","DOIUrl":"10.1016/j.jog.2023.102015","url":null,"abstract":"<div><p>Northeastern Eurasia<span> is one of the least explored regions in the world. Very little geophysical data is available for this inaccessible area. Even the exact location of the plate boundary<span><span> between Eurasia and North America remains a subject of ongoing debate. The effective elastic thickness (EET) of the lithosphere is a proxy for lithospheric strength and can provide insight into the thermal regime<span> and tectonic processes. We have computed a high-resolution map of the EET for northeastern Eurasia using the fan wavelet coherence technique applied to the Bouguer gravity anomalies<span> and topography/bathymetry data, appropriately adjusted to account for the influence of density variations within sediments. The results obtained provide insights into different tectonic regimes within this predominantly understudied region. In particular, we identify the boundary between the Eurasian and North American plates in </span></span></span>Siberia as a rheologically weak diffusive zone extending from the Verkhoyansk and Sette-Daban Ranges to the eastern boundary of the Chersky Range. Unlike the Sette-Daban and Verkhoyansk Ranges, which were formed by plate collision and have an EET of 30–50 km, other mountainous regions have much lower EET values, usually less than 15 km. These areas have recently experienced tectonic activity that has weakened the lithosphere.</span></span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"159 ","pages":"Article 102015"},"PeriodicalIF":2.3,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138987235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropic structure in the mantle wedge beneath southeastern Mexico from shear-wave splitting tomography","authors":"Samuel Celis ,&nbsp;Raúl W. Valenzuela ,&nbsp;Marco Calò ,&nbsp;Xyoli Pérez-Campos ,&nbsp;Gerardo León Soto","doi":"10.1016/j.jog.2023.102007","DOIUrl":"10.1016/j.jog.2023.102007","url":null,"abstract":"<div><p><span><span>Cocos intraslab earthquakes were used to make a 3-D tomographic inversion to define a crystallographic orientation model for the mantle wedge beneath southeastern Mexico. This model provided insights regarding the pattern of the mantle </span>wedge flow<span><span> and its relationship to the geometry of the subducting slab. The mantle wedge was parametrized as a 3-D block model of crystallographic orientations assuming the elastic constants of olivine and </span>orthopyroxene<span> with orthorhombic symmetry (hexagonal symmetry was also tested). A linearized, damped, and iterative least-squares approach was used to account for the nonlinear behavior of the shear-wave splitting, numerically recalculating partial derivatives after each iteration. The best-fitting model is consistent with two main flow regimes: (1) 2-D corner flow in a mantle wedge core made up of A-type olivine fabric northwest of the Tehuantepec Ridge extension, and (2) 3-D trench-parallel mantle flow in a mantle wedge core made up of A-, C-, or E-type olivine fabric southeast of this geological feature. Around the Tehuantepec Ridge extension, a partially serpentinized mantle wedge tip is inferred since olivine </span></span></span><em>a-</em>axis orientations are trench-parallel regardless of whether a 2-D corner flow or a 3-D trench-parallel flow prevails. Right above the Tehuantepec Ridge extension (beyond the 100 km isodepth contour of the subducting slab), a change of well-resolved olivine <em>a-</em>axis orientations from trench-normal to trench-parallel while going from northwest to southeast is observed. It signals an abrupt change in the mantle flow pattern possibly through a vertical tear in the Cocos slab. 3-D toroidal flow could be driving subslab mantle material into the mantle wedge around the deepest slab segment. Lastly, approximately trench-normal olivine <em>a-</em>axis orientations are observed in the mantle wedge tip near the Mexico and Guatemala border region, and they could be explained by assuming the presence of B-type olivine fabric.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"159 ","pages":"Article 102007"},"PeriodicalIF":2.3,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting the geodynamics of the Middle East region from an integrated geophysical perspective","authors":"Chiara Civiero ,&nbsp;Nicolas L. Celli ,&nbsp;Magdala Tesauro","doi":"10.1016/j.jog.2023.102005","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102005","url":null,"abstract":"<div><p>A long-standing question in geodynamics is whether mantle flow is driven by the plate motion alone, or mantle upwelling makes a significant contribution to it. Subducting slabs and lateral variations of the continental lithosphere can further influence the asthenospheric flow and control its direction. The Middle East region (MER) is a complex continental setting where different processes such as rifting, break-up, plate collision, and tectonic escape kinematically interact with each other. In this context, the role that lithospheric structure, mantle flow, and active upwellings may play is debated. Tomographic images provide a snapshot of the current thermal conditions of a region and seismic anisotropy can also help resolve mantle convection. Here, we synthesize shear-wave splitting observations together with up-to-date tomography models of the mantle structure beneath the MER and other geophysical data. Low-velocity anomalies are seen at asthenospheric depths beneath W Arabia, NW Iran, and Anatolia, suggesting a spreading zone of warm mantle. Two deep low-velocity bodies in Afar and Levant –interpreted as hot mantle plumes– are the sources of this shallower mantle flow. Where low velocities are imaged, we observe predominantly NE–SW oriented anisotropy, anomalously high topography, and abundant basaltic volcanism. The integrated analysis suggests that a horizontal component associated with active upwelling is present in the upper-mantle flow field. The large-scale circulation flow fed by the Afar and Levant Plumes, aided by the subduction-induced forces, facilitates the lateral motion of the Anatolian microplate and affects the dynamic evolution of the Zagros orogen. The proposed scenario demonstrates that the interplay between plate-tectonic events and mantle dynamics controls the kinematics of the region and can explain the general patterns of deformation observed at the surface.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102005"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0264370723000455/pdfft?md5=7112401fe1f8e02647a48727724233e0&pid=1-s2.0-S0264370723000455-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138467223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variation in olivine crystal-fabrics and their seismic anisotropies in the Horoman peridotite complex, Hokkaido, Japan","authors":"Kazuki Matsuyama ,&nbsp;Katsuyoshi Michibayashi","doi":"10.1016/j.jog.2023.102006","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102006","url":null,"abstract":"<div><p><span>We examined the microstructures and crystal-fabrics of peridotites<span> within a large area (6 ×5 km) of the Horoman peridotite pomplex in the Hidaka metamorphic belt of Hokkaido, Japan. Thirteen peridotite samples were analyzed for olivine and orthopyroxene grain sizes, fabric strength (</span></span><em>J-index</em><span>), and crystallographic preferred orientations (CPOs). Mean grain sizes of olivine and orthopyroxene were ranged in 295–497 µm and in 257–537 µm, respectively. The olivine fabric strength values decreased from the lower to the upper part of the complex, whereas the orthopyroxene fabric strength values showed no systematic trends. The peridotites contained three different olivine CPOs, previously known as A, E, and AG types. Combined with a previous study, we found that olivine CPOs showed a transitional distribution from E to A to AG type from south to north. E type peridotites occur at the basement of the complex in the south, suggesting that local water infiltration<span> might occur at the basement of the complex. The A type peridotites occurred mainly in the middle of the studied area and subsequently the AG type peridotites occurred towards the north. Moreover, we calculated the seismic properties of peridotite as olivine 100% aggregates and mixed (olivine and orthopyroxene) aggregates. It showed that orthopyroxene CPOs reduce P-wave anisotropies of peridotite (0.2–2.2%) without modification of the P-wave propagation patterns.</span></span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102006"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138474193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Orogen-parallel discontinuity of the Apennines subduction zone in Southern Italy as seen from mantle wedge seismic structure","authors":"Nicola Piana Agostinetti","doi":"10.1016/j.jog.2023.102004","DOIUrl":"10.1016/j.jog.2023.102004","url":null,"abstract":"<div><p>We investigate the seismic structure of the mantle wedge of the Apennines subduction zone (Central Mediterranean) using teleseismic receiver function (RF). We inverted RF for both isotropic and anisotropic properties of the mantle wedge, from below the overriding Moho to the “plate boundary”, i.e. the interface that separate the slab from the mantle wedge. Given the distribution of the seismic network, we are able to map out the change in the elastic properties at the transition between southern apennines and the Calabrian arc, given by the change in the subduction style (i.e from the subduction of continental materials to oceanic plate). We found that the anisotropy in the mantle wedge is similar between all seismic stations, generally highly anisotropic (&gt; 10%), with a direction of the symmetry axis that rotates clockwise from North to South, following the Calabrian arc geometry and likely indicating the mantle flow driven by the slab retreat. The elastic properties of the subducted crust are more heterogeneous. To the North, the subducted crust shows a highly anisotropic (&gt; 10%) behavior, and it occurs at larger depth (around 70 km depth), where to the South anisotropy is less intense (around 7%) and the subducted crust is shallower (around 60 km depth). These results point out a change in the subduction style that can be given by either a change in the metamorphic phase (more evolved blueschist facies stage to the North, initial greenschist facies stage to the South) or a different origin for the subducted materials (continental to the North and oceanic to the South). The differences in the anisotropic behavior of the subducted crust are reflected in the topography of the plate boundary, which becomes shallower from North to South, suggesting the existence of either a step in the slab topography or a more gentle ramp.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"159 ","pages":"Article 102004"},"PeriodicalIF":2.3,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0264370723000443/pdfft?md5=9aa0b6744419e827f4dc44535045b05d&pid=1-s2.0-S0264370723000443-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On constraining 3D seismic anisotropy in subduction, mid-ocean-ridge, and plume environments with teleseismic body wave data","authors":"Manuele Faccenda,&nbsp;Brandon P. VanderBeek","doi":"10.1016/j.jog.2023.102003","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102003","url":null,"abstract":"<div><p>Conventional seismic tomography studies consider the Earth’s interior as mechanically isotropic, despite seismic anisotropy being widely observed. This current standard approach to seismic imaging is likely to lead to significant artefacts in tomographic images with first-order effects on interpretations and hinders the quantitative integration of seismology with geodynamic flow models. Although a few methodologies have been proposed for carrying out anisotropic tomography, their ability in simultaneously recovering isotropic and anisotropic structures has not been rigorously tested. In this contribution we use geodynamic and seismological modeling to predict the elastic properties and synthetic teleseismic P- and S-wave travel-time datasets for three different tectonic settings: a plume rising in an intraplate setting, a divergent margin, and a subduction zone. Subsequently, we perform seismic anisotropy tomography testing a recently developed methodology that allows for the inversion of an arbitrarily oriented weakly anisotropic hexagonally symmetric medium using multiple body-wave datasets. The tomography experiments indicate that anisotropic inversions of separate and joint P- and S-wave travel-times are capable of recovering the first order isotropic velocity anomalies and anisotropic patterns. In particular, joint P- and S-wave anisotropic inversions show that by leveraging both phases it is possible to greatly mitigate issues related to imperfect data coverage common in seismology and reduce parameter trade-offs. In contrast, by neglecting seismic anisotropy, isotropic tomographic models provide no information on the mantle fabrics and in all cases are contaminated by strong velocity artifacts. In the inversions the magnitude of anisotropy (as well as that of seismic anomalies) is always underestimated owing to regularization procedures and smearing effects. It follows that the true seismic anisotropy of mantle rocks is likely higher than estimated from anisotropic tomographies, and more consistent with predictions from laboratory and numerical micro-mechanical experiments. Altogether, these results suggest that anisotropic body-wave tomography could provide unprecedented information about the Earth’s deep geological structure, and that the latter could be better recovered by complementing teleseismic body-wave travel-times with other geophysical datasets.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102003"},"PeriodicalIF":2.3,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0264370723000431/pdfft?md5=e6a25cf4922780eba6953f4420e78460&pid=1-s2.0-S0264370723000431-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92096463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Velocity anisotropy measured on the spherical specimens: History and applications","authors":"M. Petružálek ,&nbsp;T. Lokajíček ,&nbsp;R. Přikryl ,&nbsp;V. Vavryčuk","doi":"10.1016/j.jog.2023.102002","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102002","url":null,"abstract":"<div><p>The anisotropy of elastic properties, including seismic velocities, has already been investigated in the lab over past seven decades. Here, we present a review related to the development of a unique apparatus for the detailed measurement of seismic velocity anisotropy. Its originality lies in measuring velocities on spherical specimens, which allows for determination of the velocity anisotropy as a function of confining pressure loading with high resolution. The 132 directions, covering the sphere in a regular 15° net of meridians and parallels, have proven to be optimal with respect to common heterogeneities of investigated rocks. The device was designed and the first measurements were performed by a research team of the Institute of Geophysics in Prague (Babuška, Pros and Klíma) in 1968, shortly following many pioneer velocity anisotropy studies. Since then, almost 100 papers have been published using the velocity anisotropy measured with this unique device. The review consists of three separate but mutually interconnected parts: (i) historical development; (ii) microstructural insights from an ultrasonic velocity measurement perspective; (iii) macroscale applications to practical problems in geophysics, structural geology and rock mechanics.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102002"},"PeriodicalIF":2.3,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50191629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial – Geological and tectonic evolution of the Arctic","authors":"Morten Smelror,&nbsp;Oleg V. Petrov","doi":"10.1016/j.jog.2023.102001","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102001","url":null,"abstract":"","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102001"},"PeriodicalIF":2.3,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50168895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}