分类： 地球物理和空间物理 >> 应用地球物理学 >> 勘测地球物理 提交时间： 2026-04-06
摘要： 随着城市化推进，利用城市背景噪声开展被动源地震成像已成为解决地下空间探测难题的重要路径。该技术基于地震干涉理论，通过互相关处理恢复格林函数以获取地下结构信息。然而，城市环境中显著的非均匀噪声场会导致虚假震相产生，挑战了频散曲线提取的可靠性。为解决这一科学问题，分布式声学传感 (DAS) 技术利用既有光缆实现超高密度观测，有效减弱了非均匀源的影响并提升了分辨率。同时，结合物理约束的机器学习方法（如 DispFormer）显著增强了复杂数据处理的自动化与精度。这些技术的深度融合，正推动城市随机噪声向高价值探测资源的跨越式转变。
分类： 地球物理和空间物理 >> 大地测量学 >> 物理大地测量学 分类： 地球物理和空间物理 >> 地震学 提交时间： 2025-12-10
摘要： It is believed that the accumulation of small fractures (small earthquakes) in the crust is one of many ways for the formation of large fractures (large earthquakes). In such cases, the temporal variations in the accumulation number of small earthquakes can be used to predict future seismic activity in the region. To do so, a structural system of the crust is constructed using the logarithmic linear relationship between earthquake frequency and magnitude, and a relationship between earthquake accumulation and time is derived by assuming that the rate of earthquake accumulation is proportional to the q-th power of the existing number of earthquakes. Earthquake record from selected regions of China and Italy are fitted by the theory and the obtained fitting parameters are used to evaluate the future seismic activity. It is found that the extent of deviation of earthquake accumulation from the theoretical expectation can be a reasonable judgement of the local seismic dangerous level and q ≥ 1 can be considered a marker of local crust entering an accelerated fracturing phase. The proposed method made the physical evaluation of local seismic activity possible by simplifying the 3D (space-time-magnitude) problem into 2D (time-magnitude) problem in earthquake prediction.
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