pure and applied geophysics最新文献

{"title":"Role of Convective Outflows Over the Rain Shadow Region of the Indian Peninsula: A Benchmark Case Study of Long-Lasting Precipitation Event","authors":"J Sandeep,&nbsp;Thara Prabhakaran,&nbsp;Y. Jayarao,&nbsp;P. Murugavel","doi":"10.1007/s00024-024-03634-6","DOIUrl":"10.1007/s00024-024-03634-6","url":null,"abstract":"<div><p>An investigation of a linear cloud cluster (CC) that brought 7 hours of rainfall over the arid rain shadow region of peninsular India, is the topic of this study. We present detailed insights from microphysical and dynamical interactions using radar observations and cloud-resolving simulations. The cloud-resolving model at 1 km resolution simulated the cold pools and strong gust fronts close to the observation. Gust fronts and their interactions paved way for increased convection organization and aggregation. The heavy rainfall was triggered by the impact of the cold pools in the late evening hours, even though suitable conditions with low convective inhibition and high convective available potential energy were present. The enhancement of equivalent potential temperature (θ_E) within the 15 km deep layer on the intersection of gust front triggered deep moist convection. The model could simulate the precipitating core and midlevel moistening in the storm's leading edge, thereby facilitating the propagation of convection. The unique aspect is the extended area of rainfall with the two confluent gust fronts and merging of the cold pools. However, high θ_E regions were found to trigger new convection. The optimal state of the Rotunno–Klemp–Weisman (RKW) theory was noted with moderate wind shears throughout the storm lifecycle, except during the most intensified stage with significant condensate loading and strongest updrafts. The updraft mass fluxes were enhanced after the gust front intersection and have contributed to deeper convection and enhanced precipitation. The longevity of the precipitation over seven hours maybe attributed to sustained updrafts and moistening of the middle layers, triggering new convection under the influence of several cold pool outflows.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 2","pages":"815 - 842"},"PeriodicalIF":1.9,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of Seismic Anisotropy Beneath the Western Margin of Eastern Dharwar Craton, India","authors":"Bhoopendra Singh,&nbsp;K. Sivaram,&nbsp;Prantik Mandal","doi":"10.1007/s00024-024-03642-6","DOIUrl":"10.1007/s00024-024-03642-6","url":null,"abstract":"<div><p>To evaluate seismic anisotropy beneath ten broadband seismic stations in the Western margin of Eastern Dharwar Craton (EDC) (near Hyderabad region of India), we perform the shear wave splitting analysis using core refracted phases (such as SKS, SKKS) of teleseismic events. Seismic anisotropy is quantified by measuring the shear wave splitting parameters: the direction of the fast-polarized wave (Φ) and the delay time (δt) between the two components. These parameters indicate the orientation in which seismic waves travel fastest due to the material’s anisotropic properties and the strength of the anisotropy, respectively. We estimate the Φ and δt using the Rotational Correlation and Minimum Energy methods. In the upper mantle, minerals like olivine tend to align along the direction of maximum shear, as reflected in the orientation of Φ. Our results across all stations show that in a NNR NUVEL-1A, no-net- rotation reference frame, the estimated Φ and δt range from (54)° to (82)° and 0.42 to 0.90 s, respectively. The average (Φ) orientation is N(68 ± 4)⁰E, which is sub-parallel N(25 ± 4)⁰E to the absolute plate motion (APM) and the average (δt) is (0.53 ± 0.002)s. Our analysis shows discrepancy of shear wave splitting of SKS/SKKS phases which makes us believe that the source of seismic anisotropy beneath this region possibly lies in the lower mantle, as also observed in other similar studies. The observation of small (δt) lead to an interpretation of the weak anisotropy, however, due to lack of sufficient SWS data to support two—or more layers, we are not able to give a depth constraint, but the anisotropy layer may be located n the lower mantle. This observed lower mantle anisotropy may be driven by paleo-lithospheric plastic deformation in the deeper mantle (with anomalous D” structure). While under favourable temperature–pressure conditions, another possibility also exists for the phase transformation from lower mantle minerals like perovskite (Pv) to post-perovskite phase (pPv), resulting in the lattice preferred orientation (LPO) of these minerals. This observation of well detected seismic anisotropy is in contrast to many earlier researchers that had characterized this region as having either null or insignificant upper mantle seismic anisotropy. Due to sparsity of our splitting data, we are unable to constrain the depth of lower mantle anisotropy, however, this study provides valuable inputs for the studies on geodynamic evolution along the western margin of EDC.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 2","pages":"347 - 359"},"PeriodicalIF":1.9,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Inversion of Seepage Parameters by Tidal and Barometric Response Methods: A Case Study of Shizhu Well with the Thick Aquifer Mixed with Mudstones","authors":"Qiuye Yang,&nbsp;Yan Zhang,&nbsp;Junliu Suwen,&nbsp;Xiao-long Sun,&nbsp;Tianming Huang,&nbsp;Junhua Hu,&nbsp;Shengwen Qi,&nbsp;Li-Yun Fu","doi":"10.1007/s00024-024-03633-7","DOIUrl":"10.1007/s00024-024-03633-7","url":null,"abstract":"<div><p>Permeability affects the process of underground seepage, which is essential in the underground engineering field, and has significant implications for resource exploitation and the surrounding ecological environment. Tidal response analyses of the groundwater level with the leaky models can calculate permeability and judge layer leakage. However, model limitations, data quality, solution methods, etc. will affect the final calculation results and the judgment of layer leakage. In this study, the well analyzed is in the Chongqing province, and is with a relatively thick aquifer (mixed with mudstones) compared to the thickness of the aquitard. Therefore, the method of the tidal response leaky model based on the assumption of a thin aquifer could not be precisely applicable, but still could be used to do a rough estimation. Besides, we improved the barometric response leaky model, and verified the tidal response calculation results in Shizhu well, which show the result of unity. Both of the results show that during the ten years from 2009 to 2019, obvious vertical leakage occurred in the aquitard of the shallow (about 120 m deep) strata in the Shizhu area. Which calls for cautious usage of shallow groundwater for the perhaps existing vertical leakage of the surface agricultural pollutant, bacteria and pesticides into the groundwater in the Shizhu area in Chongqing Province.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 2","pages":"511 - 525"},"PeriodicalIF":1.9,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rupture Kinematics and Fault Interactions of the 2022 Mw 6.7 Luding Earthquake: Unilateral Propagation on Conjugate Faults","authors":"Jiaqi Qian,&nbsp;Wenbo Zhang,&nbsp;Ao Zheng","doi":"10.1007/s00024-024-03645-3","DOIUrl":"10.1007/s00024-024-03645-3","url":null,"abstract":"<div><p>On 5 September 2022, a <i>M</i>_w 6.7 earthquake struck the eastern edge of the Tibetan Plateau, providing a unique opportunity to analyze the Moxi seismic gap of the Xianshuihe fault. We investigate the source rupture process of the 2022 Luding earthquake by combining the back-projection imaging and the joint finite-fault inversion of strong-motion and teleseismic waveforms. We find that the Luding earthquake primarily occurred along conjugate faults, propagating southeastward along the Moxi segment and westward along the Mozigou segment. The aftershock distribution complements the main slip areas, signifying the incomplete stress release during the rupture of the mainshock. Coseismic slips are concentrated in the shallow brittle crust, with low-velocity anomalies at the lower edge of the aftershock area, suggesting middle and lower crustal flow is crucial in guiding coseismic rupture propagation and aftershock distribution. Moreover, the static Coulomb stress changes suggest that the majority of aftershocks occurred in areas with increased stress, underlining the triggering effect of the Luding mainshock. Our study also indicates the increased seismic hazard on neighboring faults, particularly on the northern segment of the Xianshuihe fault, and the Longmenshan and Gongga faults. The numerical simulation of strong ground motion indicates that the overall Peak Ground Velocity (PGV) distribution follows an elliptical shape, with higher PGV values primarily extending southward. Given the steep terrain variations and sedimentary factors in western China, our findings underscore the urgent need for enhanced earthquake resistance and disaster mitigation strategies in tectonically active areas.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 4","pages":"1397 - 1408"},"PeriodicalIF":1.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Magnetovariational Survey at Lampedusa Island for Investigating the Ambient Noise and the Subsoil Electrical Conductivity","authors":"Mauro Regi,&nbsp;Alfredo Del Corpo,&nbsp;Domenico Di Mauro,&nbsp;Stefania Lepidi,&nbsp;Paolo Bagiacchi,&nbsp;Giovanni Benedetti","doi":"10.1007/s00024-024-03632-8","DOIUrl":"10.1007/s00024-024-03632-8","url":null,"abstract":"<div><p>We conducted a magnetovariational field investigation at Lampedusa island (Italy), in the proximity to the geomagnetic observatory of Lampedusa. Data were collected from March 19 to March 23, 2022, using vector fluxgate magnetometers, configured in different spatial arrangements for two main purposes: (a) estimating the spatial distribution of potential anthropogenic noise; (b) identifying different conductivity structures beneath the observatory’s surroundings. The results obtained by means of the 1-D gradient method on simultaneous measurements indicate a very low ambient noise level, likely originating north of the geomagnetic observatory. Hypothetical event analysis, combining data from eleven sites with temporary magnetometer installations, reveals the presence of at least three distinct strata in the crust: a highly conductive layer positioned between two more resistive layers, located west of the observatory.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"167 - 187"},"PeriodicalIF":1.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03632-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Dynamic Mechanical Properties of Deep Coal Rocks Under Three-Dimensional Dynamic and Static Loading","authors":"Feng Ren,&nbsp;Chunlei Yao,&nbsp;Shuqi Xu,&nbsp;Jie Wang,&nbsp;Jiming Bao,&nbsp;Hua Chen,&nbsp;Guangchao Wei","doi":"10.1007/s00024-024-03641-7","DOIUrl":"10.1007/s00024-024-03641-7","url":null,"abstract":"<div><p>Understanding deep coal rock’s dynamic mechanical characteristics is crucial for safe design and assessment of coal rock engineering. This article tested triaxial coal samples with SHPB on deep Test coal samples and equipment using the split Hopkinson pressure bar in different conditions. Coal stress–strain curves under combined triaxial dynamic-static loading show a consistent pattern. The first axial prestress prevented compaction in the stress–strain curves. The dynamic peak stress and secant modulus of deep coal samples rose linearly with constraint pressure and strain and decreased with axial prestress. Axial prestress changes occur at 8 MPa (44% of compressive strength). The amount of energy deep coal samples absorb during impact loading varies with axial static prestress at the same strain rate and confining pressure. It rises then falls. Coal samples went from shear damage to shear and tension damage as axial static tension rose. This research helps avoid coal rock dynamic catastrophes and evaluate mining engineering stability.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"209 - 222"},"PeriodicalIF":1.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvement of Seismic Image Based on Coordinate Transformation and Incorporation of Anisotropy Factors in Seismic Velocity","authors":"Nabanita Pradhan,&nbsp;Saurabh Datta Gupta","doi":"10.1007/s00024-024-03630-w","DOIUrl":"10.1007/s00024-024-03630-w","url":null,"abstract":"<div><p>Imaging and interpreting seismic signatures in the Goru Formation of the Bandha region in the Jaisalmer Sub-basin presents unique challenges due to its complex geological structure, characterized by significant lateral velocity variations, dipping flanks, steep reflectors, and multiple fault zones. This study introduces a novel polar coordinate-velocity based Reverse Time Migration (RTM) technique that integrates anisotropic compressional velocity with transformed circumferential and radial velocities, enabling enhanced seismic imaging in such intricate geological settings. Comparative analysis of phase-shift migration, conventional cartesian velocity-based RTM, and the proposed polar velocity-based RTM demonstrate the superiority of the polar approach, which accurately captures the spherical propagation of seismic waves, particularly in anisotropic media. The findings reveal that circumferential velocity-based RTM offers superior imaging for steep dips and complex fault zones at far angles, improving fault detection accuracy, while radial velocity-based RTM excels at near angles, enhancing overall seismic resolution. In addition, conventional cartesian RTM effectively images horst and graben structures but faces limitations in steeply dipping areas. By advancing RTM methodologies with polar velocity models, this study significantly improves imaging accuracy for hydrocarbon exploration in structurally complex, anisotropic formations.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 2","pages":"491 - 509"},"PeriodicalIF":1.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of P and S Wave Phases by Machine Learning using Northwestern Türkiye Local Seismic Network Data","authors":"Utku Unal,&nbsp;Tolga Bekler","doi":"10.1007/s00024-024-03636-4","DOIUrl":"10.1007/s00024-024-03636-4","url":null,"abstract":"<div><p>In regions with intense seismic activity like earthquakes, rapid detection and resolution of earthquake parameters and understanding seismic activity and mechanisms are important in terms of reducing possible risks. Since this process is left to the knowledge and experience of users to a great extent in the solution stage, human errors in detection of seismic wave phase arrival times may negatively affect the reliability of model studies. In this study, machine learning, which has been successfully applied to data in various seismological fields, was applied to earthquakes occurring in the Biga Peninsula, encompassing the most complicated tectonic elements of the north-western Aegean region, has high window seismicity. Results were evaluated using the waveform database for events recorded by local (COMU—Çanakkale Onsekiz Mart University) and national (KOERI—Kandilli Observatory and Earthquake Research Institute, AFAD—Ministry of Interior Disaster and Emergency Management Presidency) seismic networks observing activity linked to tectonism in the region under consideration with the originally trained model of the PhaseNet machine learning algorithm. Data contains 918 earthquakes recorded at 118 stations from May 2020 to the end of 2021. Compared to classic methods, the machine learning model used in the study provided more accurate results for detecting P and S wave phases. Also, epicentre calculations based on machine learning algorithm appear to be in better spatial agreement with the distribution of active faults than calculations based on handpicks. Although the original model of PhaseNet has not been trained with local data from Türkiye, study shows it is possible to get meaningful results by making adjustments on the algorithm or applying signal processing techniques on the data. Study suggests that enhancing machine learning algorithm with local training data can improve phase detection accuracy and epicenter prediction in seismic studies.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 4","pages":"1381 - 1395"},"PeriodicalIF":1.9,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends, Patterns, and Driving Forces of Heat Waves in the Center and Southeast of Iran","authors":"Atefeh Ansari,&nbsp;Peyman Mahmoudi,&nbsp;Hamid Nazaripour,&nbsp;Sylwester Wereski","doi":"10.1007/s00024-024-03623-9","DOIUrl":"10.1007/s00024-024-03623-9","url":null,"abstract":"<div><p>In addition to negatively affecting human metabolism and biological activities, heat waves can also affect various social, economic, and industrial aspects. This study mainly investigates trends, patterns, and driving forces affecting heat waves in the center and southeast of Iran. Using the excess heat factor (EHF) index, five different characteristics of heat waves, including the heat wave number (HWN), heat wave duration (HWD), heat wave frequency (HWF), heat wave mean (HWM), and heat wave magnitude (HWA) were extracted for 15 meteorological stations in the center and southeast of Iran. Then, Sen’s slope estimator non-parametric method analyzed the long-term changes of the five characteristics of heat waves and atmospheric variables on a synoptic scale. Canonical correlation analysis (CCA) was also used to investigate the relationship between the characteristics of heat waves and the set of atmospheric variables at the synoptic scale. The study of the long-term changes in the five characteristics of heat waves in the center and southeast of Iran showed that all five characteristics have had an increasing trend for this part of Iran. In addition, the sea surface temperature (SST) of the Oman Sea, Arabian Sea, and Persian Gulf Sea have been increasing. Geopotential height at 500 hPa, air temperature at 1000 hPa, and specific humidity at two levels of 1000 and 850 hPa have also had an increasing trend on a synoptic scale. But the only variable whose long-term change trend has decreased is the zonal Wind component at three levels of 1000, 850, and 500 hPa. Therefore, it can be concluded that the long-term changes in sea surface temperature (SST), air temperature at the level of 1000 hPa, specific humidity at the level of 850 hPa, geopotential height at the height of 500 hPa, and the zonal Wind component at the levels of 1000, 850 and 500 hPa can be the most important driving forces in the explanation of long-term changes in the characteristics of heat waves in the center and southeast of Iran.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 2","pages":"903 - 928"},"PeriodicalIF":1.9,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coastal Storm Risk Reduction Using Steel Mesh Revetments: Field Application and Preliminary Physical Experiments","authors":"Mohammad Heidarzadeh,&nbsp;Mahan Sheibani,&nbsp;Roberto J. Luis-Fonseca","doi":"10.1007/s00024-024-03621-x","DOIUrl":"10.1007/s00024-024-03621-x","url":null,"abstract":"<div><p>We study coastal storm risk reduction using a steel mesh revetment system known as Tecco Cell (TC). This system consists of high-tensile stainless steel mesh filled with rock and securely fastened with tension rods. This coastal defence system is implemented in Beesands (UK), and its performance is studied here through preliminary laboratory physical modelling. The TC revetment in Beesands was installed in 2016 and has effectively protected the coast since then. We conducted 32 physical tests to assess performance criteria of a TC model in comparison to a rock armour (RA) model. Wave runup is used as the performance criterion in this study, as it is one of the key factors in coastal risk reduction research. Results showed that the TC model consistently yielded smaller runup than the RA model, with an average runup reduction of 15%. The mean spectral ratio index was employed as a measure of wave reflection and oscillations. Results indicated a mean index of 20.5 for the RA model and 3.8 for the TC model, demonstrating the potential for higher stability with the TC revetment. We established relationships between dimensionless runup and surf similarity and formulated a runup law.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"289 - 308"},"PeriodicalIF":1.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03621-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}