Seismic amplification site response on a deep-seated metamorphic slope in Southwest Japan
MA Ning1, 2, WANG Gonghui3*
(1. Faculty of Geosciences and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 611756, China;
2. Sichuan Province Engineering Technology Research Center of Ecological Mitigation of Geohazards in Xizang
Plateau Transportation Corridors, Chengdu, Sichuan 611756, China; 3. Disaster Prevention Research Institute,
Kyoto University, Kyoto, 6110011, Japan)
Abstract：Deep-seated slopes, characterized by complex geological structures and deeply incised topography, are widely distributed in the metamorphic rock terrains of the Shikoku region in western Japan. This study aims to elucidate the correlation between seismic ground motion amplification and co-seismic instability mechanisms in such slopes, focusing specifically on the Azue metamorphic rock slope located in Tokushima Prefecture. Utilizing dense microtremor observations, geophysical surveys, geological investigations, and geo-mechanical testing, we systematically analyzed the seismic response characteristics of potentially unstable slope blocks using the horizontal-to-vertical spectral ratio (HVSR) method and Time-Frequency Polarization Analysis (TFPA). The key findings are as follows: (1) The slope exhibits a multi-scale resonance structure: low-frequency resonance (3–5.5 Hz) is governed by deep-seated wave impedance interfaces, with variations in resonance amplitude (HVSR) among blocks indicating systematic differentiation in the deep structure; high-frequency resonance (8–12 Hz) correlates with shallower interfaces and demonstrates relatively uniform transitions; mid-frequency resonance (6.5–7.5 Hz) is triggered by a low-dissipation “resonant cavity” formed by a surface fracture system, resulting in discrete anomalous distributions. (2) The predominant direction of deep-seated resonance aligns with the strike of high-stiffness joints, while shallow resonance is parallel to the slope′s free face direction, reflecting the influence of stress state on wave impedance anisotropy. The fracture system induces localized resonance perpendicular to its strike. (3) Pre-existing weak layers within the slope mass transform into resonance layers exhibiting distinct wave impedance contrasts during seismic shaking, which dominate ground motion amplification and strength degradation. The synergistic amplification of seismic forces by deep, shallow, and surface “cavity” resonances predisposes the slope to large-scale bedrock sliding and shallow local instability, respectively. This investigation of the multi-scale ground motion amplification response provides a novel framework for understanding the failure mechanisms of complex deep-seated slopes during earthquakes.
马 宁1，2，王功辉3*. 西日本深层变质岩斜坡的地震放大响应特征研究[J]. 岩石力学与工程学报, 2026, 45(7): 2061-2081.
MA Ning1, 2, WANG Gonghui3*. Seismic amplification site response on a deep-seated metamorphic slope in Southwest Japan. , 2026, 45(7): 2061-2081.
[1] WASOWSKI J，KEFFER D K，LEE C T. Toward the next generation of research on earthquake-induced landslides：Current issues and future challenges[J]. Engineering Geology，2011，122(1/2)：1–8.
[2] TANYA? H，VAN WESTEN C J，ALLSTADT K E，et al. Presentation and analysis of a worldwide database of earthquake-induced landslide inventories[J]. Journal of Geophysical Research：Earth Surface，2017，122(10)：1 991–2 015.
[3] YIN Y P，WANG F W，SUN P. Landslide hazards triggered by the 2008 Wenchuan earthquake，Sichuan，China[J]. Landslides，2009，6(2)：139–152.
[4] 张永双，苏生瑞，吴树仁，等. 强震区断裂活动与大型滑坡关系研究[J]. 岩石力学与工程学报，2011，30(增2)：3 503–3 513.(ZHANG Yongshuang，SU Shengrui，WU Shuren，et al. Research on relationship between fault movement and large-scale landslide in intensive earthquake region[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(Supp.2)：3 503–3 513.(in Chinese))
[5] 范宣梅，王 欣，戴岚欣，等. 2022年MS6.8级泸定地震诱发地质灾害特征与空间分布规律研究[J]. 工程地质学报，2022，30(5)：1 504–1 516.(FAN Xuanmei，WANG Xin，DAI Lanxin，et al. Characteristics and spatial distribution pattern of MS6.8 Luding Earthquake occurred on September 5，2022[J]. Journal of Engineering Geology，2022，30(5)：1 504–1 516.(in Chinese))
[6] GÖRÜM T，TANYA? H，KARABACAK F，et al. Preliminary documentation of coseismic ground failure triggered by the February 6，2023 Türkiye earthquake sequence[J]. Engineering Geology，2023，327：107315.
[7] 罗永红，王运生. 汶川地震诱发山地斜坡震动的地形放大效应[J]. 山地学报，2013，31(2)：200–210.(LUO Yonghong，WANG Yunsheng. Mountain slope ground motion topography amplification effect induced by Wenchuan earthquake[J]. Mountain Research，2013，31(2)：200–210.(in Chinese))
[8] 殷跃平，王文沛，李 滨，等. 地层场地效应对东河口地震滑坡发生影响研究[J]. 土木工程学报，2016，49(Supp.2)：126–131.(YIN Yueping，WANG Wenpei，LI Bin，et al. Study of stratigraphic site effect on the failure mechanism of Donghekou rockslide triggered by Wenchuan earthquake[J]. China Civil Engineering Journal，2016，49(Supp.2)：126–131.(in Chinese))
[9] MA N，WANG G，KAMAI T，et al. Amplification of seismic response of a large deep-seated landslide in Tokushima，Japan[J]. Engineering Geology，2019，249：218–234.
[10] WANG Y S，MING W T，LIU J W，et al. Characteristics of slope seismic response under strong earthquake in hilly morphologic area—The case of Changning County in Sichuan Province，China[J]. Journal of Earth Sciences and Environment，2020，42(4)：540–551.(in Chinese))
[11] LIN M L，WANG K L. Seismic slope behavior in a large-scale shaking table model test[J]. Engineering Geology，2006，86：118–133.
[12] 赵 飞，俞松波，李 博，等. 地震作用下岩质边坡大型振动台试验研究进展[J]. 地球科学，2022，47(12)：4 498–4 512.(ZHAO Fei，YU Songbo，LI Bo，et al. Research advances on large-scale shaking table test for rock slopes under earthquake[J]. Earth Science，2022，47(12)：4 498–4 512.(in Chinese))
[13] CUI S H，PEI X J，YANG H，et al. Bedding slope damage accumulation induced by multiple earthquakes[J]. Soil Dynamics and Earthquake Engineering，2023，173：108157.
[14] 黄 雨，张云秋，邱振东，等. 强震作用下青藏高原地区断裂控制型边坡动力响应规律与变形破坏机制研究[J]. 中国科学：技术科学，2025，55(5)：927–942.(HUANG Yu，ZHANG Yunqiu，QIU Zhendong，et al. Dynamic response and deformation failure mechanism of fault-controlled slope in Qinghai—Xizang Plateau under strong earthquake action[J]. Scientia Sinica Technologica，2025，55(5)：927–942.(in Chinese))
[15] 朱守彪，石耀霖，陆 鸣，等. 地震滑坡的动力学机制研究[J]. 中国科学：地球科学，2013，43(8)：1 096–1 105.(ZHU Shoubiao，SHI Yaolin，LU Ming，et al. Dynamic mechanisms of earthquake-triggered landslides[J]. Science China Earth Sciences，2013，43(8)：1 096–1 105.(in Chinese))
[16] GISCHIG V S，EBERHARDT E，MOORE J R，et al. On the seismic response of deep-seated rock slope instabilities—Insights from numerical modeling[J]. Engineering Geology，2015，193：1–18.
[17] 刘毛毛，石振明，李 博，等. 基于DEM-FDM耦合的顺层岩质边坡强震动力响应及破坏模式分析[J]. 地球科学，2024，49(8)：2 799–2 812.(LIU Maomao，SHI Zhenming，LI Bo，et al. Analysis of dynamic response and failure mode of bedding rock slopes subject to strong earthquakes based on DEM-FDM coupling[J]. Earth Science，2024，49(8)：2 799–2 812.(in Chinese))
[18] AKI K，RICHARDS P G. Quantitative seismology[M]. 2nd ed. Sausalito：University Science Books，2002：677–678.
[19] SPUDICH P，HELLWEG M，LEE W H K. Directional topographic site response at Tarzana observed in aftershocks of the 1994 Northridge，California，earthquake：Implications for mainshock motions[J]. Bulletin of the Seismological Society of America，1996，86(1B)：S193–S208.
[20] MASSA M，BARANI S，LOVATI S. Overview of topographic effects based on experimental observations：meaning，causes and possible interpretations[J]. Geophysical Journal International，2014，197(3)：1 537–1 550.
[21] STOLTE A C，COX B R，LEE R C. An experimental topographic amplification study at Los Alamos National Laboratory using ambient vibrations[J]. Bulletin of the Seismological Society of America，2017，107(3)：1 386–1 401.
[22] GELI L，BARD P Y，JULLIEN B. The effect of topography on earthquake ground motion：A review and new results[J]. Bulletin of the Seismological Society of America，1988，78(1)：42–63.
[23] PAOLUCCI R. Amplification of earthquake ground motion by steep topographic irregularities[J]. Earthquake Engineering and Structural Dynamics，2002，31(11)：1 831–1 853.
[24] MEUNIER P，HOVIUS N，HAINES J A. Topographic site effects and the location of earthquake induced landslides[J]. Earth and Planetary Science Letters，2008，275(3/4)：221–232.
[25] BOZZANO F，LENTI L，MARTINO S，et al. Self-excitation process due to local seismic amplification responsible for the reactivation of the Salcito landslide(Italy) on 31 October 2002[J]. Journal of Geophysical Research：Solid Earth，2008，113(B10)：B10312.
[26] HAVENITH H B，JONGMANS D，FACCIOLI E，et al. Site effect analysis around the seismically induced ananevo rockslide，Kyrgyzstan[J]. Bulletin of the Seismological Society of America，2002，92(8)：3 190–3 209.
[27] PENG D，BO J S，QI W H，et al. The formation mechanism of low-angle loess-mudstone seismic landslides[J]. Soil Dynamics and Earthquake Engineering，2024，180：108607.
[28] KAMEDA J，KAMIYA H，MASUMOTO H，et al. Fluidized landslides triggered by the liquefaction of subsurface volcanic deposits during the 2018 Iburi—Tobu earthquake，Hokkaido[J]. Scientific Reports，2019，9：13119.
[29] MARZORATI S，LADINA C，FALCUCCI E，et al. Site effects “on the rock”：The case of Castelvecchio Subequo(L?Aquila，central Italy)[J]. Bulletin of Earthquake Engineering，2011，9(3)：841–868.
[30] MOORE J R，GISCHIG V，BURJÁNEK J，et al. Site effects in unstable rock slopes：Dynamic behavior of the Randa instability(Switzerland)[J]. Bulletin of the Seismological Society of America，2011，101(6)：3 110–3 116.
[31] KLEINBROD U，BURJÁNEK J，FÄH D. Ambient vibration classification of unstable rock slopes：A systematic approach[J]. Engineering Geology，2019，249：198–217.
[32] BURJÁNEK J，GASSNER-STAMM G，POGGI V，et al. Ambient vibration analysis of an unstable mountain slope[J]. Geophysical Journal International，2010，180(2)：820–828.
[33] 黄润秋，裴向军，李天斌. 汶川地震触发大光包巨型滑坡基本特征及形成机制分析[J]. 工程地质学报，2008，16(6)：730–741.(HUANG Runqiu，PEI Xiangjun，LI Tianbin. Basic characteristics and formation mechanism of the largest scale landslide at Daguangbao occurred during the Wenchuan Earthquake[J]. Journal of Engineering Geology，2008，16(6)：730–741.(in Chinese))
[34] HAVENITH H B，TORGOEV A，BRAUN A，et al. A new classification of earthquake-induced landslide event sizes based on seismotectonic，topographic，climatic and geologic factors[J]. Geoenvironmental Disasters，2016，3：1–14.
[35] GRAIZER V. Low-velocity zone and topography as a source of site amplification effect on Tarzana hill，California[J]. Soil Dynamics and Earthquake Engineering，2009，29(2)：324–332.
[36] HARTZELL S H，MEREMONTE M，RAMÍREZ-GUZMÁN L，et al. Ground motion in the presence of complex topography：Earthquake and ambient noise sources[J]. Bulletin of the Seismological Society of America，2014，104(1)：451–466.
[37] DEL GAUDIO V，MUSCILLO S，WASOWSKI J. What we can learn about slope response to earthquakes from ambient noise analysis：An overview[J]. Engineering Geology，2014，182：182–200.
[38] WANG G H，SUEMINE A，FURUYA G，et al. Rainstorm-induced landslides at Kisawa village，Tokushima Prefecture，Japan，August 2004[J]. Landslides，2005，2(3)：235–242.
[39] 徐义贤，罗银河. 噪声地震学方法及其应用[J]. 地球物理学报，2015，58(8)：2 618–2 636.(XU Yixian，LUO Yinhe. Methods of ambient noise-based seismology and their applications[J]. Chinese Journal of Geophysics，2015，58(8)：2 618–2 636.(in Chinese))
[40] PETERSON J. Observations and modeling of seismic background noise[R]. Albuquerque：U. S. Geological Survey，1993.
[41] OKADA H. The microtremor survey method[M]. Tulsa：Society of Exploration Geophysicists，2003：1–66.
[42] PARK C B，MILLER R D，XIA J. Multichannel analysis of surface waves[J]. Geophysics，1999，64(3)：800–808.
[43] JONGMANS D，BIÈVRE G，RENALIER F，et al. Geophysical investigation of a large landslide in glaciolacustrine clays in the Trièves area(French Alps)[J]. Engineering Geology，2009，109(1/2)：45–56.
[44] WANG G，FURUYA G，ZHANG F，et al. Layered internal structure and breaching risk assessment of the Higashi—Takezawa landslide dam in Niigata，Japan[J]. Geomorphology，2016，267：48–58.
[45] XU X Q，SU L J，ZHANG G D，et al. Analysis on shear wave velocity structure of a gravel landslide based on dual-source surface wave method[J]. Landslides，2017，14(3)：1 127–1 137.
[46] 曾 求，储日升，曾祥方，等. 利用地震背景噪声提取西山村滑坡高频面波信号[J]. 地球物理学报，2020，63(5)：1 911–1 924.(ZENG Qiu，CHU Risheng，ZENG Xiangfang，et al. Extraction of high-frequency surface waves on the Xishancun landslide from ambient seismic noises[J]. Chinese Journal of Geophysics，2020，63(5)：1 911–1 924.(in Chinese))
[47] ZHANG X，YANG Y K，GUO P，et al. Application of active and passive surface wave joint survey for 2D and 3D imaging of landslides in deeply incised terrain of the Xizang Plateau[J]. Applied Geophysics，2025，DOI：10.10071s11770–025–1293–x.
[48] WATHELET M. An improved neighborhood algorithm：Parameter conditions and dynamic scaling[J]. Geophysical Research Letters，2008，35(9)：L09301.
[49] NAKAMURA Y. A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface[J]. Quarterly Report of RTRI，1989，30(1)：25–33.
[50] 孙晓倩，储日升，曾 求，等. 利用HVSR方法探测四川理县西山村滑坡速度结构[J]. 地球物理学报，2024，67(4)：1 515–1 526.(SUN Xiaoqian，CHU Risheng，ZENG Qiu，et al. Velocity structure of the Xishancun landslide in Li County，Sichuan Province，explored by HVSR method[J]. Chinese Journal of Geophysics，2024，67(4)：1 515–1 526.(in Chinese))
[51] WITHERS M，ASTER R，YOUNG C，et al. A comparison of select trigger algorithms for automated global seismic phase and event detection[J]. Bulletin of the Seismological Society of America，1998，88(1)：95–106.
[52] PRIETO G A，PARKER R L，VERNON F L. A Fortran 90 library for multitaper spectrum analysis[J]. Computers and Geosciences，2009，35(8)：1 701–1 710.
[53] KONNO K，OHMACHI T. Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor[J]. Bulletin of the Seismological Society of America，1998，88(1)：228–241.
[54] BARD P Y，BOUCHON M. The two-dimensional resonance of sediment-filled valleys[J]. Bulletin of the Seismological Society of America，1985，75(2)：519–541.
[55] SÁNCHEZ-SESMA F J，RODRÍGUEZ M，ITURRARÁN-VIVEROS U，et al. A theory for microtremor H/V spectral ratio：Application for a layered medium[J]. Geophysical Journal International，2011，186(2)：221–225.
[56] IBS-VON SEHT M，WOHLENBERG J. Microtremor measurements used to map thickness of soft sediments[J]. Bulletin of the Seismological Society of America，1999，89(1)：250–259.
[57] 衡 帅，杨春和，张保平，等. 页岩各向异性特征的试验研究[J]. 岩土力学，2015，36(3)：609–616.(HENG Shuai，YANG Chunhe，ZHANG Baoping，et al. Experimental research on anisotropic properties of shale[J]. Rock and Soil Mechanics，2015，36(3)：609–616.(in Chinese))
[58] 邓华锋，王 伟，李建林，等. 层状砂岩各向异性力学特性试验研究[J]. 岩石力学与工程学报，2018，37(1)：112–120.(DENG Huafeng，WANG Wei，LI Jianlin，et al. Experimental study on anisotropic characteristics of bedded sandstone[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(1)：112–120.(in Chinese))
[59] DONG L J，ZHANG S，YANG L B，et al. Dynamic acoustic emission source localization and damage evolution analysis of rock under compressive loading[J]. Journal of Safety and Sustainability，2025，2(3)：147–155.
[60] CHIGIRA M，YAGI H. Geological and geomorphological characteristics of landslides triggered by the 2004 Mid Niigata prefecture earthquake in Japan[J]. Engineering Geology，2006，82(4)：202–221.
[61] DUNNING S A，MITCHELL W A，ROSSER N J，et al. The Hattian Bala rock avalanche and associated landslides triggered by the Kashmir Earthquake of 8 October 2005[J]. Engineering Geology，2007，93(3/4)：130–144.
[62] 崔圣华. 强震过程软弱层带地震响应及大型滑坡启动机制研究[博士学位论文][D]. 成都：成都理工大学，2017.(CUI Shenghua. Seismic responses of wake interlayer and initiation mechanisms of large landslide during strong earthquake[Ph. D. Thesis][D]. Chengdu：Chengdu University of Technology，2017.(in Chinese))
2026, Vol. 45 
