本日選文（共 4 篇）。

[1004] 利用KiK-net二十年資料估算日本岩手縣地下速度與共振頻率變化

Estimating subsurface velocity and resonance frequency changes using two decades of KiK-net data in the Iwate Prefecture, Japan

  • 期刊：GJI (OUP) — RSS
  • Published：Fri, 13 Mar 2026 00:00:00 GMT
  • DOI：10.1093/gji/ggag088
  • 原文連結：連結

Summary (EN) Using over two decades of KiK-net borehole–surface recordings at 28 stations in Iwate Prefecture, the authors show consistent frequency-domain (stacked Stockwell PSD) and time-domain (multitaper deconvolution and phase cross-correlation) evidence that resonance frequencies and seismic velocities systematically decrease with increasing peak ground acceleration (PGA). Frequency shifts mainly reflect the very shallow layers, while borehole-referenced velocity changes represent a path-averaged perturbation that depends on borehole depth. Across stations, relative velocity reductions average ~12% for the 200–400 cm/s^2 PGA range (implying a shear modulus reduction of ~23%), with stronger nonlinear effects at sites with thicker sedimentary deposits and no clear correlation with VS30.

重點摘要（繁中） 研究分析了岩手縣28個KiK-net站點超過20年的井下與地表記錄，並以頻域（堆疊Stockwell功率譜密度）與時域（多錐去卷積和相位互相關）方法一致地發現，隨著最高地面加速度（PGA）增加，諧振頻率與地震波速系統性下降。頻率變化主要反映最淺層，而以井下為參考估計的波速變化則為表面到井下的路徑平均，因而依賴井深。所有站點在200–400 cm/s^2 PGA範圍的相對波速降低平均約12%（對應剪模數約降低23%），非線性效應在沈積層較厚的區域更明顯，而VS30則未與非線性程度呈現明顯關聯。

[1005] 基於能量的交通燈系統（ETLS）：在注入誘發地震與滲透率增強間取得平衡之實驗室尺度模型研究

Energy-based traffic light system (ETLS) to balance injection-induced seismicity and permeability enhancement: a laboratory scale modelling study

  • 期刊：GJI (OUP) — RSS
  • Published：Mon, 09 Mar 2026 00:00:00 GMT
  • DOI：10.1093/gji/ggag094
  • 原文連結：連結

Summary (EN) The authors propose an energy-based traffic light system (ETLS) that uses the seismic injection efficiency (seismic energy divided by hydraulic energy) to manage hydraulic shear stimulation and reduce injection-induced seismicity. They numerically model a naturally rough, slowly slipping, velocity-strengthening granite fracture using a rate-and-state friction framework with aperture evolving with slip and slip velocity, and compare ETLS-controlled injection to monotonic and cyclic injection. Results show ETLS reduces slip velocity by 30% relative to monotonic injection (whereas cyclic injection increased slip velocity by 51%), while achieving similar aperture per injected volume at larger injection volumes, suggesting ETLS can lower seismic risk while maintaining permeability enhancement.

重點摘要（繁中） 作者提出一種基於能量的交通燈系統（ETLS），以地震注入效率（地震能量與水力能量之比）來管理液壓剪切增透以降低誘發地震風險。研究以速率-狀態摩擦框架數值模擬天然粗糙、緩慢滑移且速度強化的花崗岩裂縫，裂縫孔隙度隨滑移位移與滑移速度演化，並將ETLS注入與單調及循環注入比較。結果顯示ETLS較單調注入可使滑移速度降低30%（而循環注入則增加51%），且在較大注入量下能維持與單調注入相近的每體積增孔隙效果，表示ETLS可在維持增透效益的同時降低滑移速率與地震風險。

[1007] 斷層構造與地震危害：來自 2024 年 M_W 5.2 貝克斯菲爾德地震序列的洞見

Faulting structure and seismic hazard: Insights from the 2024 MW 5.2 Bakersfield earthquake sequence

  • 期刊：Tectonophysics (ScienceDirect)
  • DOI：10.1016/j.tecto.2026.231184
  • 原文連結：連結

Summary (EN) The 2024 M_W 5.2 Bakersfield earthquake near the White Wolf Fault produced unexpectedly strong shaking about 10 km from the epicenter, well above empirical predictions. Using machine-learning-derived high-resolution catalogs, the authors resolve a buried NW–SE-striking secondary fault at 12–15 km depth, offset ~5 km from the main surface trace, and aftershock distribution and focal mechanisms indicate rupture propagated along this subsidiary structure. Ground motions were strongly amplified by site effects in the thick sedimentary Maricopa sub-basin, and no foreshocks were recorded in the four hours before the mainshock, consistent with aseismic nucleation on a buried fault. The study concludes that silent rupture initiation combined with basin amplification can greatly increase seismic hazard to cities in sedimentary basins.

重點摘要（繁中） 2024年在White Wolf斷層附近發生的M_W 5.2 Bakersfield地震，在距震中約10公里處造成超出經驗預測的強烈搖晃。作者利用機器學習產生的高解析率地震目錄，解析出一條埋藏於12–15公里深、走向NW–SE、較地表White Wolf主斷層偏移約5公里的次要斷層，餘震分布與震源機制顯示破裂沿此次要構造傳播。厚厚的Maricopa副盆沉積層導致場址放大效應，顯著放大地面運動；在主震前四小時未觀測到前震，與埋藏斷層上的無聲成核相符。研究結論為：無聲的破裂啟動與盆地放大共同提升了沉積盆地內城市的地震危害。

[1020] 基於輸入能量頻譜的微動水平對垂直頻譜比

Microtremor horizontal-to-vertical spectral ratio based on input-energy spectra

  • 期刊：Earth-Science Reviews (ScienceDirect)
  • DOI：10.1016/j.enggeo.2026.108710
  • 原文連結：連結

Summary (EN) The paper introduces a new microtremor horizontal-to-vertical spectral ratio (MHVSR) method based on input-energy spectra, deriving its theoretical expression and analyzing its properties. Tested on microtremor records from 104 sites in Japan with borehole data, the method yields a smoothed, unique alternative to the traditional Fourier amplitude spectrum (FAS) approach without subjective smoothing and, unlike a response-spectra-based method, markedly reduces sensitivity to long-period noise and unrealistic rising trends. The proposed approach produces more stable spectral ratio curves and is particularly effective when the site fundamental period is shorter than about 0.7 s.

重點摘要（繁中） 本研究提出以輸入能量頻譜為基礎的微震水平對垂直光譜比（MHVSR）新方法，推導其理論表達式並系統分析其性質。利用日本104處站點的微震與鑽孔資料驗證後，該方法提供了比傳統傅立葉振幅頻譜（FAS）更為平滑且唯一的結果，免除主觀平滑處理；且與響應譜法相比，顯著降低對長週期雜訊的敏感性，抑制不合理的遞增趨勢。該方法可產生更穩定的光譜比曲線，當場址基頻小於約0.7秒時尤為適用。