pure and applied geophysics最新文献

{"title":"Novel Optimal Staggered Grid Finite Difference Scheme Based on Gram–Schmidt Procedure for Acoustic Wave Modelling","authors":"Min Zhang,&nbsp;Liming Zhou,&nbsp;Daiguang Fu,&nbsp;Shiqi Dong,&nbsp;Haibo Wu","doi":"10.1007/s00024-024-03652-4","DOIUrl":"10.1007/s00024-024-03652-4","url":null,"abstract":"<div><p>The staggered grid finite difference method is used extensively in numerical simulations of acoustic equations; however, its application is accompanied by numerical dispersion. The most representative traditional method for suppressing the numerical dispersion is the Taylor expansion method, which primarily converts the acoustic equation into a polynomial equation of the trigonometric function and subsequently expands the trigonometric function into a power function polynomial through the Taylor expansion to finally obtain the difference coefficient. However, this traditional method is only applicable to the small wavenumber range. In this study, the Gram–Schmidt orthogonalization method, combined with the binomial theorem and Euler formula was used to reverse the polynomial of power function into a polynomial of trigonometric function and to obtain a new difference coefficient. To highlight the effectiveness of the proposed method, it was compared with the Taylor expansion method (TEM) and the least-squares method (LSM) by selecting a small wavenumber, middle wavenumber, and wide wavenumber ranges. Accuracy and dispersion analyses were conducted. The results showed that the new difference coefficient generated smaller errors and induced stronger suppression of the numerical dispersion. A comparative analysis of the uniform and complex models further validated the superiority of the proposed staggered grid difference coefficient.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"271 - 287"},"PeriodicalIF":1.9,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480999","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":"Correction: Assessing the Spatial and Temporal Characteristics of Meteorological Drought in Afghanistan","authors":"Gokmen Tayfur,&nbsp;Ehsanullah Hayat,&nbsp;Mir Jafar Sadegh Safari","doi":"10.1007/s00024-024-03650-6","DOIUrl":"10.1007/s00024-024-03650-6","url":null,"abstract":"","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"309 - 309"},"PeriodicalIF":1.9,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480998","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":"Estimation of the Gutenberg-Richter Seismic Hazard Parameters: A Way to Take into Account Isolated Earthquakes—Application to the Alps Domain","authors":"Anne Dutfoy","doi":"10.1007/s00024-024-03655-1","DOIUrl":"10.1007/s00024-024-03655-1","url":null,"abstract":"<div><p>Depending on the time period and geographical location, the collection of seismic data has been more or less exhaustive and systematic. Thus, seismic catalogues contain some isolated seismic events. This information is usually excluded from the inference process of the recurrence model. In this paper, we assume that earthquakes are modelled by a stationary Poisson point process, under the Gutenberg-Richter assumption. We propose a way to take that information into account by adapting the expression of the likelihood of the Poisson point process. In addition, we consider that the completeness magnitude varies in time.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"29 - 44"},"PeriodicalIF":1.9,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480899","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":"Microzonation Through Seismic and Geotechnical Vulnerability Assessment: Recommendation of Foundation Selection Guidelines for the Srinagar Metropolitan Region","authors":"Falak Zahoor,&nbsp;K. Seshagiri Rao,&nbsp;Neelima Satyam","doi":"10.1007/s00024-024-03644-4","DOIUrl":"10.1007/s00024-024-03644-4","url":null,"abstract":"<div><p>The paper presents the microzonation of Srinagar Metropolitan Region (SMR) located in the Himalayas which is exposed to a high level of seismic risk due to its critical tectonic setting. In an effort to improvise the microzonation process for the region, seismic hazard assessment has been combined with geotechnical vulnerability estimation to define vulnerability zones. An integrated hazard index (<i>IHI</i>), indicative of the vulnerability of a site, was estimated by combining a bearing capacity hazard index and a liquefaction hazard index for each site. Based on the value of <i>IHI</i>, four vulnerability zones viz. VZ-A (<i>IHI</i> &lt; 0.15), VZ-B (<i>IHI</i> 0.15–0.30), VZ-C (<i>IHI</i> 0.30–0.55), and VZ-D (<i>IHI</i> &gt; 0.55), representing low to high vulnerability, have been defined for the region. Subsequently, hilly areas in the region were categorised as VZ-A; floodplains as VZ-C,D; and Karewa highlands as VZ-B,C. General guidelines have been recommended for the selection of appropriate foundations and ground improvement techniques within these zones. The proposed approach models an application of microzonation as a direct input for the design of foundations of structures and intends to complement the Master-Plan 2035 for the ongoing urban development in the SMR.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"79 - 105"},"PeriodicalIF":1.9,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480904","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":"Elastic Impedance Reconstruction Using Compound First- and Second-Order Total Variation Regularization","authors":"Kasra Nazmehr,&nbsp;Mohammad Ali Riahi,&nbsp;Amir Jamasb","doi":"10.1007/s00024-024-03629-3","DOIUrl":"10.1007/s00024-024-03629-3","url":null,"abstract":"<div><p>This study introduces a novel compound regularization technique for Elastic Impedance (EI) inversion that combines Total Variation (TV1) and Total Variation of the second-order (TV2) regularizations. This method leverages the Split-Bregman algorithm to effectively address the staircase effect, a common limitation of using TV1 regularization alone. The proposed approach enforces smoothness (TV1) and improved edge preservation (TV2) in the reconstructed EI models, leading to more accurate representations. The efficacy of this method is demonstrated by applying it to two geologically relevant elastic models: the Marmousi model (complex but synthetic) and seismic field data from the Gulf of Mexico. Numerical tests were conducted using realistic noise levels, and the results confirmed the proposed method’s ability to reconstruct detailed and accurate EI models for both models, highlighting its generalizability to diverse geological scenarios. Unlike the simpler TV1 and TV2 regularizations, our combined approach adeptly handles complex models featuring both smooth and abrupt transitions, though its performance can vary across different geological scenarios. This method provides a promising framework for improved EI reconstruction in diverse geological settings.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"125 - 139"},"PeriodicalIF":1.9,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481199","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":"Combining Envelope Inversion and Full Waveform Inversion for Velocity Model Building Using OBN Data","authors":"Min Ouyang,&nbsp;Wenrui Ye,&nbsp;Dun Deng,&nbsp;Xingguo Huang,&nbsp;Xiaodong Luo","doi":"10.1007/s00024-024-03649-z","DOIUrl":"10.1007/s00024-024-03649-z","url":null,"abstract":"<div><p>Oil and gas constitute a significant part of marine resources, whose exploration and production routinely rely on geophysical seismic data to improve existing databases. Traditional seismic datasets have suffered from extensive ambiguity due to the combined effects of thermal fluids, fractures, shallow velocity anomalies, and mid-deep layer bottom structure. Actual situation displays that despite several previous reprocessing efforts, the quality of seismic data in some ambiguous areas has only been partially improved, while the resolution issues remain unresolved. Given the poor seismic imaging quality and extraordinarily low signal-to-noise ratio data, it is challenging to determine the accurate structural features. To tackle this challenge, we combine the analysis of wavefield attenuation characteristics and high-precision velocity modeling as well as inversion methods to depict the subsurface areas. We aim at provide a validate high-quality seismic data processing and inversion method to determine an accurate velocity model to support the interpretation of actual geological data. We introduce the low-frequency reconstructed envelope inversion and investigate GPU/CPU paralleled full waveform inversion (FWI) method. We demonstrate the efficacy of our method by using both synthetic data and field data from a certain sea area in China. Numerical results indicate that a combination of low-frequency reconstructed envelope inversion and full waveform inversion can effectively improve the accuracy of the existing velocity data for more than 25%.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"141 - 165"},"PeriodicalIF":1.9,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481200","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":"Probing the Complex Interaction of Makran Subduction Zone with Regional Tectonic Features: Insights from Gravity and Seismic Source Parameters","authors":"Raja Adnan Habib,&nbsp;Muhammad Tahir Iqbal,&nbsp;Mohammad Salam,&nbsp;Mohammad Tahir,&nbsp;Javed Iqbal,&nbsp;Talat Iqbal","doi":"10.1007/s00024-024-03631-9","DOIUrl":"10.1007/s00024-024-03631-9","url":null,"abstract":"<div><p>Unraveling the intricate tectonic framework of the Makran subduction zone is essential for enhancing our understanding of seismic risks and developing effective mitigation strategies. This study delves into this complexity by analyzing gravity data and stress states derived from earthquake focal mechanisms. In this endeavor, the distribution and nature of seismic activity were compared with lateral gravity variations observed through vertical changes at the near-surface, intermediate, and regional levels. This analysis revealed a strong correlation between abrupt gravity changes and earthquake occurrences. This study reveals contrasting stress regimes across subduction zones and associated tectonic elements. Along the deformation front of the subduction zone, predominantly north−south compression occurred, and greater coupling in the eastern part was inferred based on gravity data. Northward, an anti-clockwise rotation of the stress axis is consistent with regional tectonics and deep structures within the Afghan Block, possibly influenced by the Chaman Transform Boundary to the east. The same northeast−southwest trend is followed by a deep normal faulting band related to the flexure of the subducted Arabian plate, which exhibits complex behavior, particularly in the west, where it seems to detach from the eastern part and interact with the deep root of the Sistan Suture. The same interaction may be responsible for the comparatively higher seismic activity in the western part of the flexural structure. The presence of a low-density zone below 100 km depth implies that two deep earthquakes occurring underneath the Chaghi volcanic arc discordant with the general trend of tectonic features and the stress axis may be associated to contortion in the subducting Arabian Plate under the effect of deep root’s Indo-Eurasian plate boundary.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"55 - 77"},"PeriodicalIF":1.9,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481154","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":"Aircraft Studies of Horizontal and Inclined Spectra of Wind Velocity Fluctuations in the Stably-Stratified Troposphere","authors":"Igor Chunchuzov,&nbsp;Oleg Popov,&nbsp;Sergey Kulichkov,&nbsp;Otto Chkhetiani","doi":"10.1007/s00024-024-03637-3","DOIUrl":"10.1007/s00024-024-03637-3","url":null,"abstract":"<div><p>In this paper, we study tropospheric wind velocity fluctuation spectra measured both along horizontal aircraft tracks over Greenland and along inclined aircraft tracks during their ascents and descents. This study is done based on the analysis of the global and long-term high-resolution dataset of meteorological parameters measured by civil aircrafts. The transition from the Nastrom-Gage spectrum with a slope of -5/3 in the horizontal scale-range of 6–200 km to a steeper part of the spectrum at shorter scales is analyzed. Based on the results of wind measurements along 82 inclined trajectories of airplanes during their ascent and descent in the troposphere, the vertical wave number spectra of wind velocity fluctuations measured along these trajectories as a function of height (hereinafter referred to as inclined spectra) were obtained. From the obtained horizontal and inclined spectra of the wind velocity fluctuations their anisotropy (the ratio of horizontal-to-vertical scale) is estimated. The obtained spectra are interpreted using models of 3-D and 1-D (horizontal and vertical) wavenumber spectra of the wind velocity fluctuations. The tropospheric vertical wave number spectra of anisotropic wind velocity fluctuations obtained from the aircraft measurements during ascents and descents (altitudes 5–10 km) are compared to the vertical wave number spectra of the wind velocity fluctuations in the stratosphere and mesosphere retrieved from the infrasound signals generated by ground-based explosions and volcanic eruptions. The general physical mechanism of formation of the fine layered structure of wind velocity for both the stably-stratified layers of the troposphere and the stratosphere-mesosphere is discussed.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"235 - 254"},"PeriodicalIF":1.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481230","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":"Research on Microseismic Periodic Noise Suppression Method Based on Long Short-Term Memory Network","authors":"Xulin Wang,&nbsp;Minghui Lv","doi":"10.1007/s00024-024-03643-5","DOIUrl":"10.1007/s00024-024-03643-5","url":null,"abstract":"<div><p>The signal-to-noise ratio of ground-truth microseismic data is relatively low. Most of the current noise suppression methods are effective in dealing with random noise but neglect the periodic noise present in the microseismic data, leading to poor denoising effects. To address this issue, this paper proposes a new noise suppression method that combines short-time stationarity tests with Long Short-Term Memory (LSTM) algorithms to suppress periodic noise in microseismic data. By processing both simulated and field data and comparing the results with the traditional Variational Mode Decomposition (VMD) algorithm, the experimental results demonstrate that the method proposed in this paper can more effectively suppress periodic background noise in microseismic data, thereby enhancing the signal-to-noise ratio of the data.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"107 - 123"},"PeriodicalIF":1.9,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481035","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 Applicability of Point-Source Models in Ground-Motion Prediction","authors":"Igor A. Beresnev","doi":"10.1007/s00024-024-03646-2","DOIUrl":"10.1007/s00024-024-03646-2","url":null,"abstract":"<div><p>Point-source simulations with simple functional shapes of radiated Fourier spectra are widely used in earthquake-hazard assessments. Such an approximation is based on two physical assumptions: that (1) all near-field phenomena and (2) the wave-interference effects, caused by fault finiteness, are negligibly small (the far-field and the point-source approximations, respectively). The limits of applicability of these assumptions can be deduced from the complete theoretical description of the seismic field radiated by a fault rupture, expressed in the representation integral of elasticity. The far-field condition, deduced directly from the representation integral, is controlled by the slip and the slip rate on the fault; for a <i>M</i>_<i>w</i> 4 earthquake (<i>M</i>_<i>w</i> is the moment magnitude), it is reasonably satisfied at the distance of a few hundred meters. The point-source approximation is not satisfied even for the smallest earthquakes considered in seismic hazards: for a <i>M</i>_<i>w</i> 4 earthquake, the radiated finite-fault spectra significantly deviate from the commonly postulated omega-square shapes already at the frequencies around 1 Hz and above. The interference phenomena caused by fault finiteness act as a high-cut filter, creating the observed deficit in the high-frequency energy not accounted for by point-source spectra. To correct, the point-source models apply ad-hoc filtering, such as the kappa operator, acting as a substitute for the filtering naturally created by the fault itself. The finite-fault spectra without additional filtering can be formally explained by an equivalent point source with the kappa operator applied. The <i>κ</i> values determined from the equivalent point-source spectrum are in the same range as those empirically observed. However, if a finite-fault spectrum is interpreted as a point-source one with kappa, the values of the maximum slip velocity, an influential physical parameter of rupture, are recovered incorrectly. The kappa filtering can be fully explained by the finite-fault effects always present in all earthquakes of practical significance.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 1","pages":"45 - 53"},"PeriodicalIF":1.9,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481036","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}