Earthquake Science最新文献_第2页

High resolution catalog of the Luxian (Sichuan, China) MS6.0 earthquake sequence and analysis of the seismogenic structures

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2025-02-01 DOI: 10.1016/j.eqs.2024.09.004

Huili Guo , Dahu Li , Pingping Wu , Qiyan Yang , Ningbo Jiang , Mi Gao , Zhifeng Ding

The epicenter of the Luxian M_S6.0 earthquake on September 16, 2021, was located in the southern Sichuan Basin, which is a historically seismically quiescent area. In recent years, the frequency of earthquakes has increased with the large-scale exploitation of shale gas. No evident surface fractures or seismic faults were observed after the Luxian earthquake. Based on high-quality data recorded by a dense seismic array composed of 70 portable stations with an average spacing of 2–3 km, a high-resolution seismic catalog was constructed for 7 days before and 36 days after the M_S6.0 earthquake using LOC-FLOW, an effective workflow of phase picking, phase association, and earthquake location. Based on the new earthquake catalog, four earthquake clusters that occurred within the Yujiasi Syncline during this period were identified. Among them, the M_S6.0 main earthquake sequence had a NW-SE trend and inclined towards the SW, with a length of approximately 8 km and width of 5 km. The M_S6.0 earthquake sequence only appeared after the mainshock. The other three clusters were located in the northeast direction of the M_S6.0 earthquake sequence, all of which were NE-SW trending strips and had no evident direct correlation with the M_S6.0 mainshock. The focal depth was concentrated in the range of 2–7 km. Based on the seismic sequence profile and structural background, the M_S6.0 seismic structure may be a blind buried fault zone with a NW strike composed of multiple small conjugate faults with NE and SW dip. The fault was not exposed on the surface and was related to the detachment structure in the deep part of the Sichuan Basin.

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引用次数: 0

An illustrated guide to: Distributed and integrated fibre-optic sensing in seismology

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2025-02-01 DOI: 10.1016/j.eqs.2024.09.006

Andreas Fichtner , Fabian Walter , Patrick Paitz , Sara Klaasen , Daniel C. Bowden , Sebastian Noe , Nils Müller , Dominik Husmann , Jacques Morel

The properties of laser signals are affected by deformation of the optical fibre through which they are transmitted. While this deformation dependence is undesirable in telecommunication, it can be exploited for the construction of novel seismic sensors that fill a niche in data acquisition where traditional seismometer arrays would be difficult to deploy. This includes densely populated urban centers, the oceans, volcanoes and the Earth’s polar regions. These notes complement a presentation on recent methodological developments and applications in fibre-optic seismology. The first part is focused on the use of distributed fibre-optic sensing in cryosphere research, and specifically the investigation of the internal structure and seismicity of glaciers and ice sheets. The second part is dedicated to recent advances in integrated fibre-optic sensing, with emphasis on novel measurement principles and sensitivity.

引用次数: 0

Machine learning-based aftershock seismicity of the 2015 Gorkha earthquake controlled by flat-ramp geometry and a tear fault

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2025-02-01 DOI: 10.1016/j.eqs.2024.05.002

Yeyang Kuang , Jiangtao Li

The Main Himalayan Thrust (MHT), where the 2015 M_W7.8 Gorkha earthquake occurred, features the most seismicity of any structure in Nepal. The structural complexity of the MHT makes it difficult to obtain a definitive interpretation of deep seismogenic structures. The application of new methods and data in this region is necessary to enhance local seismic hazard analyses. In this study, we used a well-designed machine learning-based earthquake location workflow (LOC-FLOW), which incorporates machine learning phase picking, phase association, absolute location, and double-difference relative location, to process seismic data collected by the Hi-CLIMB and NAMASTE seismic networks. We built a high-precision earthquake catalog of both the quiet-period and aftershock seismicity in this region. The seismicity distribution suggests that the quiet-period seismicity (388 events) was controlled by a mid-crustal ramp and the aftershock seismicity (12,669 events) was controlled by several geological structures of the MHT. The higher-level detail of the catalogs derived from this machine learning method reveal clearer structural characteristics, showing how the flat-ramp geometry and a possible duplex structure affect the depth distribution of the seismic events, and how a tear fault changes this distribution along strike.

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引用次数: 0

Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experiment

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2025-02-01 DOI: 10.1016/j.eqs.2024.05.001

Lu Zhang , Chen Cai , Rui Gao

Magmatism at continental margins is of great significance in understanding the continental rifting. We present a two-dimensional P-wave velocity model derived from an ocean bottom seismometer experiment, conducted across the middle northern continental margin of the South China Sea (SCS). The detailed velocity structures reveal significant heterogeneities extending from the continental shelf to the continent-ocean transition zone. The crust exhibits its greatest thickness below the continental shelf, measuring ∼23 km and gradually thins to ∼13 km at the distal margin. Furthermore, a narrow and distinct continent-ocean transition with only 40-km width is revealed. We also observe a high-velocity layer within the transition zone, reaching thickness of up to 4 km, characterized by P-wave velocities ranging from 7.0 km/s to 7.6 km/s in the lower crust. Based on the syn-rift melt generation using decompression melting model, we ascertain that syn-rift magmatism cannot fully account for the observed thick high-velocity layer. By integrating findings from previous geophysical and geochemical studies presenting extensive volcanic edifice on the seafloor at the northern margin, as well as ocean-island-basalt-type magmatic samples in the SCS area, we propose that post-rifting magmatism associated with the Hainan Plume may have influenced the formation of the high-velocity lower crust within the transition zone and the northern margin of the SCS can thus be recognized as magma-poor type margin.

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引用次数: 0

Structural similarity of lithospheric velocity models of Chinese mainland 中国大陆岩石圈速度模型的结构相似性

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.05.004

Feng Huang , Xueyang Bao , Qili Andy Dai , Xinfu Li

Existing lithospheric velocity models exhibit similar structures typically associated with the first-order tectonic features, with dissimilarities due to different data and methods used in model generation. The quantification of model structural similarity can help in interpreting the geophysical properties of Earth’s interior and establishing unified models crucial in natural hazard assessment and resource exploration. Here we employ the complex wavelet structural similarity index measure (CW-SSIM) active in computer image processing to analyze the structural similarity of four lithospheric velocity models of Chinese mainland published in the past decade. We take advantage of this method in its multiscale definition and insensitivity to slight geometrical distortion like translation and scaling, which is particularly crucial in the structural similarity analysis of velocity models accounting for uncertainty and resolution. Our results show that the CW-SSIM values vary in different model pairs, horizontal locations, and depths. While variations in the inter-model CW-SSIM are partly owing to different databases in the model generation, the difference of tomography methods may significantly impact the similar structural features of models, such as the low similarities between the full-wave based FWEA18 and other three models in northeastern China. We finally suggest potential solutions for the next generation of tomographic modeling in different areas according to corresponding structural similarities of existing models.

现有岩石圈速度模型表现出类似的结构，通常与一阶构造特征有关，但由于生成模型时使用的数据和方法不同而存在差异。模型结构相似性的量化有助于解释地球内部的地球物理特性，并建立对自然灾害评估和资源勘探至关重要的统一模型。在此，我们采用计算机图像处理中常用的复小波结构相似性指数（CW-SSIM）来分析近十年来发表的四个中国大陆岩石圈速度模型的结构相似性。我们利用了该方法的多尺度定义以及对平移和缩放等轻微几何失真的不敏感性，这在考虑不确定性和分辨率的速度模型结构相似性分析中尤为关键。我们的研究结果表明，CW-SSIM 值在不同的模型对、水平位置和深度都存在差异。虽然模型间 CW-SSIM 值的差异部分是由于模型生成过程中数据库的不同造成的，但层析成像方法的不同可能会对模型的相似结构特征产生重大影响，例如基于全波的 FWEA18 与中国东北地区其他三个模型之间的相似度较低。最后，我们根据现有模型的相应结构相似性，提出了不同地区下一代层析成像模型的潜在解决方案。

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引用次数: 0

An illustrated guide to: Parsimonious multi-scale full-waveform inversion 图解指南准多尺度全波形反演

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.07.004

Andreas Fichtner, Solvi Thrastarson, Dirk-Philip van Herwaarden, Sebastian Noe

Having been a seemingly unreachable ideal for decades, 3-D full-waveform inversion applied to massive seismic datasets has become reality in recent years. Often achieving unprecedented resolution, it has provided new insight into the structure of the Earth, from the upper few metres of soil to the entire globe. Motivated by these successes, the technology is now being translated to medical ultrasound and non-destructive testing. Despite remarkable progress, the computational cost of full-waveform inversion continues to be a major concern. It limits the amount of data that can be exploited, and it largely inhibits quantitative and comprehensive uncertainty analyses. These notes complement a presentation on recent developments in full-waveform inversion that are intended to reduce computational cost and assimilate more data, thereby improving tomographic resolution. The suite of strategies includes flexible and user-friendly spectral-element simulations, the design of wavefield-adapted meshes that harness prior information on wavefield geometry, dynamic mini-batch optimisation that naturally takes advantage of data redundancies, and collaborative multi-scale updating to jointly constrain crustal and mantle structure.

几十年来，三维全波形反演一直是一个看似遥不可及的理想，但近年来，应用于海量地震数据集的三维全波形反演已成为现实。它通常能达到前所未有的分辨率，为人们提供了对地球结构的新认识，从上层几米深的土壤到整个地球。在这些成功经验的推动下，这项技术目前正被应用于医学超声波和无损检测。尽管取得了显著进展，全波形反演的计算成本仍然是一个主要问题。它限制了可利用的数据量，并在很大程度上阻碍了定量和全面的不确定性分析。这些说明是对全波形反演最新发展的补充，旨在降低计算成本，吸收更多数据，从而提高层析分辨率。这套策略包括灵活和用户友好的谱元模拟、利用波场几何先验信息的波场适应网格设计、自然利用数据冗余的动态小批量优化，以及联合约束地壳和地幔结构的协作式多尺度更新。

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引用次数: 0

Evaluation of crustal deformation and associated strong motions induced by the 2022 Paktika earthquake, Afghanistan 对 2022 年阿富汗帕克蒂卡地震诱发的地壳变形和相关强烈运动的评估

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.07.001

A. Bari Jahed , Ömer Aydan , Takashi Ito , Naoki Iwata

The 2022 Paktika earthquake (moment magnitude: 6.2) occurred on June 22, 2022, near the border between the Khost and Paktika Provinces of Afghanistan, causing heavy damage and casualties in Paktika Province. This study evaluated the crustal deformation and associated strong motions induced by the Paktika earthquake. Crustal deformations were determined using the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique and three-dimensional finite element method (3D-FEM) and the results were compared. The permanent ground displacements obtained from the DInSAR and 3D-FEM analyses were similar in terms of amplitude and areal distribution. Strong motions were estimated using the 3D-FEM with and without considering regional topography. The estimations of maximum ground acceleration, velocity, and permanent ground deformations were compared among each other as well as with those inferred from failures of some simple structures in the Spera and Gayan districts. The inferred maximum ground acceleration and velocity from the failed adobe structures were more than 300 Gal and 50 cm/s, respectively, nearly consistent with the estimates obtained using empirical methods. The empirical method yielded a maximum ground acceleration of 347 Gal, whereas the maximum ground velocity was approximately 50 cm/s. In light of these findings, some surface expressions of crustal deformations and strong ground motions, such as failures of soil and rock slopes and rockfalls, have been presented. The rock slope failures in the epicentral area were consistent with those observed during various earthquakes in Afghanistan and worldwide.

2022 年 6 月 22 日，阿富汗霍斯特省和帕克蒂卡省交界处附近发生了 2022 年帕克蒂卡地震（震级：6.2 级），给帕克蒂卡省造成了严重破坏和人员伤亡。本研究评估了帕克蒂卡地震引起的地壳变形和相关强烈运动。使用差分干涉合成孔径雷达（DInSAR）技术和三维有限元法（3D-FEM）确定了地壳变形，并对结果进行了比较。差分干涉合成孔径雷达和三维有限元法分析得出的永久地表位移在振幅和方圆分布上相似。在考虑和不考虑区域地形的情况下，使用三维有限元估算了强运动。对最大地面加速度、速度和永久地面变形的估算结果进行了相互比较，并与斯佩拉和加扬地区一些简单结构的破坏推断结果进行了比较。从倒塌的土坯结构中推断出的最大地面加速度和速度分别超过 300 Gal 和 50 cm/s，与使用经验方法得出的估计值基本一致。经验方法得出的最大地面加速度为 347 加仑，而最大地面速度约为 50 厘米/秒。根据这些研究结果，提出了地壳变形和强烈地面运动的一些表面表现形式，如土石斜坡崩塌和落石。震中地区的岩坡崩塌与在阿富汗和世界各地的各种地震中观察到的岩坡崩塌一致。

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引用次数: 0

Seismogenic model of the 2023 MW5.5 Pingyuan earthquake in North China Plain and its tectonic implications 2023 年华北平原 MW5.5 级平原地震的成震模式及其构造影响

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.06.008

Shiguang Wang , Libo Han , Junju Xie , Liping Fan , Xiang Huang , Jinmeng Bi , Hongfeng Yang , Lihua Fang

The 6 August 2023 M_W5.5 Pingyuan earthquake is the largest earthquake in the central North China Plain (NCP) over the past two decades. Due to the thick sedimentary cover, no corresponding active faults have been reported yet in the epicenter area. Thus, this earthquake presents a unique opportunity to delve into the buried active faults beneath the NCP. By integrating strong ground motion records, high-precision aftershock sequence relocation, and focal mechanism solutions, we gain insights into the seismotectonics of the Pingyuan earthquake. The aftershocks are clustered at depths ranging from 15 to 20 km and delineate a NE-SW trend, consistent with the distribution of ground motion records. A NE-SW nodal plane (226°) of the focal mechanism solutions is also derived from regional waveform inversion, suggesting that the mainshock was dominated by strike-slip motion with minor normal faulting component. Integrating regional geological data, we propose that an unrecognized fault between the NE-SW trending Gaotang and Lingxian-Yangxin faults is the seismogenic fault of this event. Based on the S-wave velocity structure beneath the NCP, this fault probably extends into the lower crust with a high angle. Considering the tectonic regime and stress state, we speculate that the interplay of shear strain between the Amurian and South China blocks and the hot upwelling magma from the subducted paleo Pacific flat slab significantly contributed to the generation of the Pingyuan earthquake.

2023 年 8 月 6 日 MW5.5 级平远地震是华北平原中部近二十年来最大的地震。由于沉积覆盖层较厚，震中地区尚未发现相应的活动断层。因此，此次地震为深入研究华北平原地下埋藏的活动断层提供了一个难得的机会。通过整合强地震动记录、高精度余震序列重定位和焦点机制解，我们对平远地震的地震构造有了更深入的了解。余震集中在 15 至 20 千米深的区域，呈东北-西南走向，与地动记录的分布一致。区域波形反演也得出了焦点机制解的东北-西南结点面（226°），表明主震以冲滑运动为主，伴有少量正断层成分。综合区域地质资料，我们提出在 NE-SW 走向的高塘断层和凌县-阳新断层之间的一条未被识别的断层是此次事件的发震断层。根据国家地质公园下方的 S 波速度结构，该断层可能以高角度延伸至地壳下部。考虑到构造体系和应力状态，我们推测阿穆尔块体和华南块体之间的剪切应变以及来自俯冲古太平洋平板的热上涌岩浆的相互作用是平远地震发生的重要原因。

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引用次数: 0

Assessing the effects of model parameter assumptions on surface-wave inversion results 评估模型参数假设对面波反演结果的影响

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.07.002

Xuezhen Zhang , Xiaodong Song

Surface-wave inversion is a powerful tool for revealing the Earth’s internal structure. However, aside from shear-wave velocity (v_S), other parameters can influence the inversion outcomes, yet these have not been systematically discussed. This study investigates the influence of various parameter assumptions on the results of surface-wave inversion, including the compressional and shear velocity ratio (v_P/v_S), shear-wave attenuation (Q_S), density (ρ), Moho interface, and sedimentary layer. We constructed synthetic models to generate dispersion data and compared the obtained results with different parameter assumptions with those of the true model. The results indicate that the v_P/v_S ratio, Q_S, and density (ρ) have minimal effects on absolute velocity values and perturbation patterns in the inversion. Conversely, assumptions about the Moho interface and sedimentary layer significantly influenced absolute velocity values and perturbation patterns. Introducing an erroneous Moho-interface depth in the initial model of the inversion significantly affected the v_S model near that depth, while using a smooth initial model results in relatively minor deviations. The assumption on the sedimentary layer not only affects shallow structure results but also impacts the result at greater depths. Non-linear inversion methods outperform linear inversion methods, particularly for the assumptions of the Moho interface and sedimentary layer. Joint inversion with other data types, such as receiver functions or Rayleigh wave ellipticity, and using data from a broader period range or higher-mode surface waves, can mitigate these deviations. Furthermore, incorporating more accurate prior information can improve inversion results.

面波反演是揭示地球内部结构的有力工具。然而，除了剪切波速度（vS），其他参数也会影响反演结果，但这些参数尚未得到系统讨论。本研究探讨了各种参数假设对地表波反演结果的影响，包括压缩和剪切速度比（vP/vS）、剪切波衰减（QS）、密度（ρ）、莫霍面和沉积层。我们构建了合成模型来生成频散数据，并将不同参数假设下获得的结果与真实模型的结果进行了比较。结果表明，vP/vS 比值、QS 和密度 (ρ) 对绝对速度值和反演中的扰动模式影响很小。相反，对莫霍面和沉积层的假设对绝对速度值和扰动模式有很大影响。在反演的初始模型中引入一个错误的莫霍界面深度，会对该深度附近的 vS 模型产生重大影响，而使用一个平滑的初始模型则会产生相对较小的偏差。对沉积层的假设不仅会影响浅层结构的结果，还会影响更大深度的结果。非线性反演方法优于线性反演方法，特别是对莫霍界面和沉积层的假设。与其他数据类型（如接收函数或瑞利波椭圆度）联合反演，以及使用更宽周期范围或更高模式的面波数据，可以减少这些偏差。此外，采用更准确的先验信息也能改善反演结果。

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引用次数: 0

An open access dataset for strong-motion data (PGA, PGV, and Site VS) of 2023 M6.2 Jishishan, Gansu, China earthquake 2023 年中国甘肃积石山 M6.2 级地震强震数据（PGA、PGV 和场地 VS）的开放访问数据集

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science

Pub Date : 2024-09-26 DOI: 10.1016/j.eqs.2024.04.002

Jian Zhou , Li Li , Nan Xi , Kun Chen , Xin Tian , Chao Wang , Jifeng Tian

引用次数: 0