Geoscience Letters最新文献

Seasonal and interannual variations of soil heterotrophic respiration and autotrophic respiration in subtropical forests of southeast China: independent process-based models. 中国东南部亚热带森林土壤异养呼吸和自养呼吸的季节和年际变化：基于独立过程的模型

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2025-01-01 Epub Date: 2025-06-21 DOI: 10.1186/s40562-025-00399-1

Yibo Yan, Xiujun Wang, Georg Wohlfahrt, Ni Huang

Soil respiration consists of two distinctive components: heterotrophic respiration (decomposition of soil organic matter) and autotrophic respiration (CO₂ production from root system), which are driven by different factors. However, the absence of process-based independent models for the two components hampers our ability to accurately quantify and understand the key carbon sources on land. Here, we used observational data to develop independent models for both soil heterotrophic and autotrophic respiration in the subtropical forests of southeast China, and validated the models using independent field data. Applying the validated models, we estimated both soil heterotrophic respiration and autotrophic respiration at three forest sites over 2002-2022. Our results showed higher annual rates of heterotrophic respiration (0.8-1.6 g C m^-2 day^-1) than autotrophic respiration (0.5-0.8 g C m^-2 day^-1). There was significant seasonality and inter-annual variability in both components, with larger variations in autotrophic respiration. The inter-annual variation was strongest in the winter season for both two respiration components. We found a significant (p < 0.01) increasing trend in autotrophic respiration (with a slope of 2.0-6.0 g C m^-2 year^-2) but not in heterotrophic respiration over 2002-2022. There was also a significant increasing trend in total soil respiration (3.4-6.2 g C m^-2 year^-2 for slopes), indicating an increasing role of autotrophic respiration. Our results reveal the dynamic nature of soil heterotrophic respiration and autotrophic respiration and their differing responses to environmental changes, emphasizing the need for independent models to improve the understanding of soil CO₂ sources in a changing climate.

Supplementary information: The online version contains supplementary material available at 10.1186/s40562-025-00399-1.

土壤呼吸由异养呼吸（土壤有机质分解）和自养呼吸（根系产生二氧化碳）两部分组成，它们受不同因素的驱动。然而，缺乏基于过程的两个组成部分的独立模型阻碍了我们准确量化和理解陆地上关键碳源的能力。本文利用观测资料建立了中国东南部亚热带森林土壤异养和自养呼吸的独立模型，并利用独立的野外数据对模型进行了验证。应用验证过的模型，我们估算了2002-2022年三个森林样地的土壤异养呼吸和自养呼吸。我们的研究结果显示异养呼吸（0.8-1.6 g C - m-2 day-1）的年速率高于自养呼吸（0.5-0.8 g C - m-2 day-1）。两组分均存在显著的季节性和年际变化，其中自养呼吸变化较大。两组分的年际变化均以冬季最强。在2002-2022年期间，我们发现异养呼吸显著（p -2年），但没有。土壤总呼吸也有显著增加的趋势（坡地为3.4 ~ 6.2 g C m-2），表明自养呼吸的作用日益增强。我们的研究结果揭示了土壤异养呼吸和自养呼吸的动态性质及其对环境变化的不同响应，强调了在气候变化中需要建立独立的模型来提高对土壤CO2源的认识。补充资料：在线版本包含补充资料，下载地址：10.1186/s40562-025-00399-1。

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引用次数: 0

The effectiveness of machine learning methods in the nonlinear coupled data assimilation 机器学习方法在非线性耦合数据同化中的有效性

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-09-18 DOI: 10.1186/s40562-024-00347-5

Zi-ying Xuan, Fei Zheng, Jiang Zhu

Implementing the strongly coupled data assimilation (SCDA) in coupled earth system models remains big challenging, primarily due to accurately estimating the coupled cross background-error covariance. In this work, through simplified two-variable one-dimensional assimilation experiments focusing on the air–sea interactions over the tropical pacific, we aim to clarify that SCDA based on the variance–covariance correlation, such as the ensemble-based SCDA, is limited in handling the inherent nonlinear relations between cross-sphere variables and provides a background matrix containing linear information only. These limitations also lead to the analysis distributions deviating from the truth and miscalculating the strength of rare extreme events. However, free from linear or Gaussian assumptions, the application of the data-driven machine learning (ML) method, such as multilayer perceptron, on SCDA circumvents the expensive matrix operations by avoiding the explicit calculation of background matrix. This strategy presents comprehensively superior performance than the conventional ensemble-based assimilation strategy, particularly in representing the strongly nonlinear relationships between cross-sphere variables and reproducing long-tailed distributions, which help capture the occurrence of small probability events. It is also demonstrated to be cost-effective and has great potential to generate a more accurate initial condition for coupled models, especially in facilitating prediction tasks of the extreme events.

在耦合地球系统模式中实施强耦合数据同化（SCDA）仍然具有很大的挑战性，这主要是由于需要准确估计耦合交叉背景-误差协方差。在这项工作中，我们通过简化的两变量一维同化试验，重点研究热带太平洋上空的海气相互作用，旨在阐明基于方差-协方差相关性的 SCDA（如基于集合的 SCDA）在处理跨球变量之间固有的非线性关系方面存在局限性，并且只能提供包含线性信息的背景矩阵。这些局限性也会导致分析分布偏离事实，并误判罕见极端事件的强度。然而，在 SCDA 上应用数据驱动的机器学习（ML）方法（如多层感知器），可以摆脱线性或高斯假设，避免显式计算背景矩阵，从而规避昂贵的矩阵运算。与传统的基于集合的同化策略相比，这种策略具有全面的优越性能，特别是在表示跨球变量之间的强非线性关系和再现长尾分布方面，这有助于捕捉小概率事件的发生。该方法还被证明具有成本效益，而且在为耦合模式生成更准确的初始条件方面具有巨大潜力，尤其是在促进极端事件的预测任务方面。

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引用次数: 0

Volcanic activity around Taipei, Taiwan: new data and perspectives on the Tatun Volcano Group 台湾台北周边的火山活动：大屯火山群的新数据和新视角

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-09-13 DOI: 10.1186/s40562-024-00358-2

Su-Chin Chang, Mei-Fei Chu, Jui-Pin Wang, Yu-Ming Lai, Sheng-Rong Song, Sidney R. Hemming, Samuel Wai-Pan Ng, Timothy Dylan Chow

The Tatun Volcano Group (TVG) is located at the northern end of Taiwan, ~ 15 km from the center of Taipei, a metropolitan area of over seven million inhabitants. A volcanic eruption by the TVG of any type or scale could cause catastrophic human and economic impacts. This paper summarizes previous geochemical, geophysical, and geochronological reports and highlights why the widely accepted age model does not comport with the latest observations. This study also reports novel 40Ar/39Ar ages for two andesite samples and one basalt sample from the TVG. A sample collected from Chihsingshan yields a robust 40Ar/39Ar age of 0.081 ± 0.005 Ma. This provides the first direct evidence of TVG volcanic activity after 0.1 Ma. Two samples yield 0.28 ± 0.02 Ma for Tatunshan and 0.159 ± 0.017 Ma for Honglushan. The younger ages refute previously proposed age models for the TVG. Along with new drone photos and LiDAR images, the age data help resolve eruptive history and advance understanding of volcanic hazards and hazard mitigation in Taiwan and surrounding areas.

大屯火山群（TVG）位于台湾北端，距台北市中心约 15 公里，台北市是一个拥有 700 多万居民的大都会区。任何类型或规模的大屯火山群火山爆发都可能对人类和经济造成灾难性影响。本文总结了之前的地球化学、地球物理和地质年代报告，并强调了为什么广泛接受的年龄模型与最新观测结果不符。本研究还报告了来自 TVG 的两个安山岩样本和一个玄武岩样本的新 40Ar/39Ar 年龄。从赤兴山采集的一个样本得到了可靠的 40Ar/39Ar 年龄，即 0.081 ± 0.005 Ma。这首次提供了 TVG 火山活动在 0.1 Ma 之后的直接证据。在两个样品中，大屯山的年龄为 0.28 ± 0.02 Ma，红芦山的年龄为 0.159 ± 0.017 Ma。较年轻的年龄驳斥了之前提出的 TVG 年龄模型。这些年龄数据与新的无人机照片和激光雷达图像一起，有助于解析火山爆发历史，加深对台湾及周边地区火山灾害和减灾的了解。

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引用次数: 0

A snapshot of the climate in the Middle Pleistocene inferred from a stalagmite from central Japan 从日本中部的石笋推断中更新世的气候快照

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-09-09 DOI: 10.1186/s40562-024-00357-3

Masataka Sakai, Masako Hori, Ryu Uemura, Bassam Ghaleb, Daniele L. Pinti, Mahiro Yumiba, Masafumi Murayama, Akihiro Kano

Stalagmites are useful archives in reconstructing paleoclimates: most paleoclimate studies used stalagmites that are distributed in specific locations and ages. We examined a stalagmite (GYM-1) collected from Nara Prefecture, central Japan, where limestone areas are limited. Applying 238U–234U method, the ages of GYM-1 were determined as 744 ± 70 to 677 ± 74 ka (based only on analytical uncertainties, 1σ). Even assuming a 10% uncertainty in the initial activity of 234U/238U, (234U/238U)0, this age could be still older than 460 ka. Temperatures calculated based on δD in the fluid inclusions and δ18O in the calcium carbonate ranged from 9.0 to 11.9 °C (10.8 ± 0.9 °C on average) or from 6.0 to 9.1 °C (7.9 ± 0.9 °C on average) depending on the equation. The estimated temperature suggests that GYM-1 formed during an interglacial period of the Middle Pleistocene. Synchronous behavior of isotopic values with lamination likely reflects seasonal temperature in a highly ventilated cave system.

石笋是重建古气候的有用档案：大多数古气候研究都使用分布在特定地点和年代的石笋。我们研究了从石灰岩地区有限的日本中部奈良县采集的石笋（GYM-1）。应用 238U-234U 方法，确定了 GYM-1 的年龄为 744 ± 70 至 677 ± 74 ka（仅基于分析不确定性，1σ）。即使假设 234U/238U 的初始活度（234U/238U）0 有 10%的不确定性，这个年龄仍可能早于 460 ka。根据流体包裹体中的δD 和碳酸钙中的δ18O 计算出的温度范围为 9.0 至 11.9 °C（平均为 10.8 ± 0.9 °C）或 6.0 至 9.1 °C（平均为 7.9 ± 0.9 °C），具体取决于方程。估计温度表明，GYM-1 形成于中更新世的间冰期。同位素值与层理的同步行为很可能反映了高度通风的洞穴系统中的季节性温度。

引用次数: 0

The crustal deformation mechanism of southern Chuandian block: constrained by S wave velocity and its azimuthal anisotropy 南川店地块地壳变形机制：S波速度及其方位各向异性的约束

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-27 DOI: 10.1186/s40562-024-00355-5

Zaiji Gao, Ya Sun, Jiwen Huang, Qiu Li

We construct the 3D Shear wave velocity and azimuthal anisotropy images in the southern Chuandian block using phase velocity dispersion of Rayleigh wave in the period of 5–45 s. The images show two extensive low-velocity zones with a depth range of 20–40 km. The west range of the low-velocity extends from the Lijiang-Xiaojinhe fault to the Red River fault, while its east range follows along the Xiaojiang fault. Two ranges of low velocities are merged at the southern inner belt of the Emeishan Large Igneous Provinces (ELIP). The observed fast directions of azimuthal anisotropy are consistent with the extension of low-velocity ranges at the lower crust. The findings reveal the presence of two potential weak channels in the lower crust, characterized by low-velocity zones, which align with the hypothesis of lower crustal flow. Meanwhile, the crust around the inner belt of ELIP exhibits a high-velocity body characterized by a northeast-trending and counter-clockwise azimuthal anisotropy. Combined with geological data, we attribute the high S-velocity to a mafic–ultramafic magma reservoir of the ELIP, which blocks the continuity of crustal flow within the southern Chuandian block, thus dividing the lower crustal flow into two branches. Additionally, we also find the fast directions of azimuthal anisotropy above 20 km align well with the strike-slip fault orientations. The above research results indicate that the crustal deformation in the southern Chuandian block is likely attributed to the joint action of the two deformation mechanisms. One involves a lower crustal flow model, while the other entails rigid extrusion controlled by the deep-seated, large-scale strike-slip faults in the upper crust.

利用瑞利波5-45秒的相位速度频散，构建了川地块南部的三维剪切波速度和方位各向异性图像。西部低速带从丽江-小金河断层延伸至红河断层，东部低速带则沿小金河断层延伸。两条低速带在峨眉山大火成岩带南部内带汇合。观测到的快速方位各向异性方向与低速范围在地壳下部的延伸一致。研究结果表明，下地壳存在两个潜在的弱通道，其特征是低速区，这与下地壳流动的假说一致。同时，ELIP内带周围的地壳呈现出一个高速体，其特征是呈东北走向和逆时针方位各向异性。结合地质资料，我们将高S向速度归因于ELIP的黑云母-超黑云母岩浆储层，它阻断了南川地块内地壳流动的连续性，从而将下地壳流动分为两支。此外，我们还发现20千米以上方位各向异性的快速方向与走向滑动断层的走向十分吻合。上述研究结果表明，南川地块的地壳变形很可能是两种变形机制共同作用的结果。一种是下地壳流动模式，另一种是上地壳深层大尺度走向滑动断层控制的刚性挤压。

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引用次数: 0

Surface air temperature anomalies over Antarctica and the Southern ocean induced by interactions between the interdecadal Pacific oscillation and Atlantic multidecadal oscillation 太平洋年代际振荡和大西洋年代际振荡相互作用诱发的南极洲和南大洋表面气温异常现象

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-22 DOI: 10.1186/s40562-024-00352-8

Lejiang Yu, Shiyuan Zhong, Cuijuan Sui, Bo Sun

Previous research has explored the impact of the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) on Antarctic surface air temperature (SAT) variability. However, a notable gap remains in our comprehension concerning the response of Antarctic SAT to the four phase combinations of IPO and AMO. In this study, we unveil unique patterns of Antarctic SAT anomalies during four distinct sub-periods based on the phases of IPO and AMO. Notably, Antarctic SAT anomalies exhibit a considerable seasonality, with the most pronounced (weakest) anomalies occurring during the austral winter (summer), a phenomenon consistent across all four sub-periods. These different anomalous SST patterns trigger varying convective rainfall patterns, consequently initiating distinct wavetrains that propagate into the Southern Ocean. These different wavetrains, in turn, induce variations in sea level pressure and surface wind fields, resulting in different Antarctic SAT anomalies primarily through mechanisms related to horizontal thermal advection and downward longwave radiation. Understanding the variability in Antarctic surface air temperature (SAT) is crucial for unraveling the complex dynamics of the polar climate system and its broader implications for global climate patterns. Fewer studies highlighted the impacts of the four combinations of the phases of IPO and AMO on Antarctic SAT anomalies. In this study, we uncover distinct patterns of Antarctic SAT anomalies during four different periods based on the phases of IPO and AMO. We note that Antarctic SAT anomalies exhibit a considerable seasonality, with the most pronounced (weakest) anomalies occurring during the austral winter (summer), consistently across all four periods. The anomalous SST patterns during different periods trigger distinct wavetrains that propagate into the Southern Ocean, inducing variations in sea level pressure, surface wind fields, and Antarctic SAT anomalies. These findings bear substantial implications for the prediction of Antarctic seasonal SAT variations on interdecadal timescales.

以往的研究探讨了年代际太平洋涛动（IPO）和大西洋多年涛动（AMO）对南极表面气温（SAT）变化的影响。然而，我们在理解南极 SAT 对 IPO 和 AMO 的四个阶段组合的响应方面仍存在明显差距。在本研究中，我们根据 IPO 和 AMO 的不同阶段，揭示了南极 SAT 异常在四个不同子时期的独特模式。值得注意的是，南极 SAT 异常表现出相当强的季节性，最明显（最微弱）的异常出现在澳大利亚的冬季（夏季），这一现象在所有四个子时期都是一致的。这些不同的海温异常模式触发了不同的对流降雨模式，从而引发了传播到南大洋的不同波系。这些不同的波系反过来又引起海平面气压和海面风场的变化，主要通过与水平热平流和向下长波辐射有关的机制导致不同的南极 SAT 异常。了解南极表面气温（SAT）的变化对于揭示极地气候系统的复杂动态及其对全球气候模式的广泛影响至关重要。较少研究强调 IPO 和 AMO 的四个阶段组合对南极 SAT 异常的影响。在本研究中，我们根据 IPO 和 AMO 的不同阶段，发现了南极 SAT 异常在四个不同时期的不同模式。我们注意到，南极 SAT 异常表现出相当强的季节性，最明显（最微弱）的异常出现在澳大利亚的冬季（夏季），这在所有四个时期都是一致的。不同时期的海温异常模式会引发不同的波系，传播到南大洋，引起海平面气压、表面风场和南极 SAT 异常的变化。这些发现对预测南极季节性 SAT 在年代际尺度上的变化具有重大意义。

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引用次数: 0

Distribution and trend of explosive cyclones over the Southern Ocean and associated atmospheric and oceanic changes during 1980–2020 1980-2020 年期间南大洋爆炸性气旋的分布和趋势以及相关的大气和海洋变化

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-22 DOI: 10.1186/s40562-024-00356-4

Xiaoqi Xu, Jiping Liu, Gang Huang, Yifan Ding

In this study, we investigate the climatology and trend of explosive cyclones (ECs) over the Southern Ocean (50oS–70oS) during 1980–2020 by combining a method that is most suited for identifying and tracking cyclones in the Southern Ocean and a latest climate reanalysis. On average, approximately 50 ECs are generated annually over the Southern Ocean, with a significant increasing trend of 2.3 per decade during the studying period. This increasing trend is dominated by the trend of strong ECs, particularly in autumn. We analyze the dynamical and thermodynamical effects associated with multiple deepened strong ECs in autumn over an identified key region in the southern Pacific Ocean sector (155oW–170oW, 50oS–65oS), where the density of the initiation of ECs shows the largest increasing trend in autumn. The composite analysis reveals the general patterns and duration of the effects on the atmosphere, ocean, and sea ice associated with multiple ECs in the southern Pacific Ocean. The results indicate that the deepened strong ECs are associated with significant changes in meridional winds, downward longwave radiation, and sensible and latent heat fluxes. These changes lead to cold sea surface temperature anomalies in the northeast of the key region, reaching a maximum 5–7 days after the EC deepening, and the increased sea ice cover south of the key region, peaking 4–5 days after the EC deepening.

在本研究中，我们结合最适合识别和跟踪南大洋气旋的方法和最新的气候再分析，研究了 1980-2020 年期间南大洋（50oS-70oS）上空的爆发性气旋（ECs）的气候学和趋势。在研究期间，南大洋上空平均每年产生约 50 个气旋，并呈显著增加趋势，每十年增加 2.3 个。这种增加趋势主要是强EC的趋势，特别是在秋季。我们分析了秋季在南太平洋扇区（155oW-170oW，50oS-65oS）一个已确定的关键区域上空多次加深的强 EC 的相关动力学和热力学效应，在该区域，EC 的起始密度在秋季呈现出最大的增长趋势。综合分析揭示了与南太平洋多EC相关的大气、海洋和海冰效应的一般模式和持续时间。结果表明，强 EC 的加深与经向风、向下长波辐射以及显热和潜热通量的显著变化有关。这些变化导致关键区域东北部海面温度异常变冷，在EC加深后5-7天达到最大值；关键区域南部海冰覆盖面积增加，在EC加深后4-5天达到峰值。

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引用次数: 0

Seismogenic structures along the deformation front from onshore to offshore SW Taiwan 台湾西南部从陆地到近海沿变形前沿的成震结构

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-14 DOI: 10.1186/s40562-024-00354-6

Wen-Nan Wu, Jing-Yi Lin, Wen-Bin Doo, Chung-Liang Lo, Shu-Kun Hsu

Accurately imaging seismogenic structures is crucial for seismic hazard assessment. This is especially important around the deformation front (DF) region off SW Taiwan, where seismic potential is high but the fault structure and seismic activity are still poorly understood. Here, we present a comprehensive delineation of seismogenic structures along the onshore and offshore DF of SW Taiwan, utilizing hypocenter relocations and first-motion focal mechanism solutions from January 1991 to March 2019. Five distinctive seismogenic structures are delineated. Particularly, the energetic seismic activity initialled after the 2017 Mw5.3 Tainan earthquake and migrated northeastward along the western side of the DF. The offshore trace of the DF could serve as a boundary delimiting the seismic activity driven by the flexural stress of the subducted Eurasia Plate to the west of the DF. This observation could constrain the magnitude estimation of future earthquakes offshore SW Taiwan. Meanwhile, the areas with higher seismic moment release are located near the DF rather than known faults, indicating that the DF may dominate the seismic moment release. However, further study is warranted into the intricate relationship among seismic strain variation, the structure of DF, and seismic activity to further understand the seismic potential. Our first-motion focal mechanism solutions show that several earthquakes in SW Taiwan were characterized by P-axis orientations parallel to the strike of the Taiwan orogeny. Those events are preferably explained by the lateral compression induced by the ongoing collision between the Eurasia and Philippine Sea plates.

精确成像震源结构对于地震灾害评估至关重要。这一点在台湾西南部近海的变形前沿（DF）地区尤为重要，该地区的地震潜力很高，但人们对其断层结构和地震活动仍知之甚少。在此，我们利用 1991 年 1 月至 2019 年 3 月期间的次中心重定位和初动焦点机制解决方案，对台湾西南部陆上和近海 DF 沿线的成震结构进行了全面划分。共划分出五个不同的成震结构。特别是，高能地震活动始于 2017 年 Mw5.3 台南地震之后，并沿 DF 西侧向东北方向迁移。DF 的离岸迹线可作为划定 DF 西侧俯冲欧亚板块挠曲应力驱动的地震活动的边界。这一观测结果可对未来台湾西南部近海地震的震级估计产生制约作用。同时，地震力矩释放较高的区域位于DF附近而非已知断层，表明DF可能主导地震力矩释放。然而，地震应变变化、DF 结构和地震活动性之间的复杂关系有待进一步研究，以进一步了解地震潜力。我们的一动焦机制解表明，台湾西南部的几个地震具有与台湾造山运动走向平行的 P 轴方向的特征。欧亚板块和菲律宾海板块之间的持续碰撞所引起的横向压缩可以解释这些地震事件。

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引用次数: 0

The western extension of the Balantak Fault revealed by the 2021 earthquake cascade in the central arm of Sulawesi, Indonesia 2021 年印度尼西亚苏拉威西岛中臂级联地震揭示的巴兰塔克断层西延问题

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-14 DOI: 10.1186/s40562-024-00353-7

Andrean V. H. Simanjuntak, Kadek H. Palgunadi, Pepen Supendi, Umar Muksin, Endra Gunawan, Sri Widiyantoro, Nicholas Rawlinson, Mudrik R. Daryono, D. Daryono, Dwikorita Karnawati, Nuraini R. Hanifa, Cecep Pratama, Rachmah Ida

Two shallow earthquakes of moment magnitude 6.2 and 5.8 occurred in the central arm of Sulawesi on 26 July 2021 and 26 August 2021, respectively. The fault responsible for the earthquake had previously only been partially mapped, thus making further analysis of its characteristics crucial for the assessment of seismic hazard. In this study, we exploit data from a regional seismic network, relocate the associated seismicity using the double difference method with an updated velocity model, determine focal mechanisms from full-waveform inversion, and analyze the static stress changes caused by the mainshock. Our relocated hypocenters and focal mechanism solutions reveal two earthquake clusters, one at the Central Balantak Fault that exhibits normal slip on a SE–NW trending rupture, and the other at the West Balantak Fault, which exhibits dextral strike-slip motion on a SE–NW trending rupture. The additional static stress increase transferred by the Mw 6.2 mainshock may have triggered the subsequent Mw 5.8 event. A detailed assessment of previously unmapped faults in Central Sulawesi is essential for a more comprehensive understanding of seismic hazard in the region.

2021 年 7 月 26 日和 2021 年 8 月 26 日，苏拉威西岛中部臂区分别发生了两次震级分别为 6.2 级和 5.8 级的浅层地震。发生地震的断层之前只绘制了部分地图，因此进一步分析其特征对于评估地震危害至关重要。在本研究中，我们利用区域地震台网的数据，采用更新速度模型的双差分法重新定位相关地震，通过全波形反演确定病灶机制，并分析主震引起的静应力变化。我们重新定位的次中心和焦点机制解决方案揭示了两个地震群，一个位于巴兰塔克断层中部，在一条东南-西北走向的断裂上呈现正向滑动；另一个位于巴兰塔克断层西部，在一条东南-西北走向的断裂上呈现右旋走向滑动。6.2 级主震传递的额外静应力增加可能引发了随后的 5.8 级地震。要更全面地了解中苏拉威西地区的地震危害，就必须对以前未绘制地图的断层进行详细评估。

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引用次数: 0

Precursory seismic quiescence of major earthquakes along the Sagaing fault zone, central Myanmar: application of the pattern informatics technique 缅甸中部实皆断陷带大地震的前震静止：模式信息学技术的应用

IF 4 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geoscience Letters

Pub Date : 2024-08-07 DOI: 10.1186/s40562-024-00351-9

Premwadee Traitangwong, Sutthikan Khamsiri, Santi Pailoplee

In this study, the precursory seismic activity before a major earthquake was investigated by using the Pattern Informatics (PI) algorithm along the Sagaing fault zone (SFZ), Central Myanmar. After improving the earthquake catalog, the completeness of seismicity data with Mw ≥ 3.6 reported during 1980–2020 was used in retrospective testing to find the suitable parameters of the PI algorithm. According to the retrospective test with 6 cases of different forecast period times related to Mw ≥ 5.0 earthquakes, including verification using the relative operating characteristics (ROC) diagram, the characteristic parameters of both time intervals (change time and forecast time window) = 10 years and target forecast earthquake magnitude Mw ≥ 5.0 are suitable parameters for PI investigation along the SFZ. Therefore, these parameters were applied with the most up-to-date seismic dataset to evaluate the prospective areas of upcoming major earthquakes. The results reveal that the Myitkyina and the vicinity of Naypyidaw might be at risk of a major earthquake in the future. Therefore, effective earthquake mitigation plans should be urgently arranged.

本研究利用模式信息学（PI）算法对缅甸中部实皆断陷带（SFZ）大地震前的前兆地震活动进行了研究。在完善地震目录后，利用 1980-2020 年间报道的 Mw ≥ 3.6 的地震数据的完整性进行回顾性测试，以找到 PI 算法的合适参数。根据与 Mw ≥ 5.0 地震相关的 6 个不同预报周期时间案例的回顾性测试，包括使用相对运算特征（ROC）图进行验证，时间间隔（变化时间和预报时间窗口）= 10 年和目标预报震级 Mw ≥ 5.0 这两个特征参数是适合沿 SFZ 进行 PI 调查的参数。因此，应用这些参数和最新地震数据集来评估即将发生大地震的潜在区域。结果表明，密支那和内比都附近地区未来可能会发生大地震。因此，应立即安排有效的防震减灾计划。

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引用次数: 0