Continuous ambient seismic monitoring of potentially unstable sites is increasingly attracting the attention of researchers for precursor recognition and early warning purposes. Twelve cases of long-term continuous noise monitoring have been reported in the literature between 2012 and 2020. Only in a few cases rupture was achieved and irreversible drops in resonance frequency values or shear wave velocity extracted from noise recordings were documented. On the other hand, all monitored sites showed clear reversible fluctuations of the seismic parameters on a daily and seasonal scale due to changes in external weather conditions (air temperature and precipitation). A quantitative comparison of these reversible modifications is used to gain insight into the mechanisms driving the site seismic response. Six possible mechanisms were identified, including three temperature-driven mechanisms (temperature control on fracture opening/closing, superficial stress conditions and bulk rigidity), one precipitation-driven mechanism (water infiltration effect) and two mechanisms sensitive to both temperature and precipitation (ice formation and clay behavior). The reversible variations in seismic parameters under the meteorological constraints are synthesized and compared to the irreversible changes observed prior to failure in different geological conditions.

对潜在不稳定地点的连续环境地震监测越来越引起研究人员的关注，以进行前体识别和预警。据报道，2012年至2020年之间有12例长期连续噪声监测。只有少数情况发生破裂，并且记录了从噪声记录中提取的共振频率值或剪切波速度的不可逆下降。另一方面，由于外部天气条件（气温和降水）的变化，所有监测站点在日常和季节性尺度上均显示出明显的可逆地震参数波动。这些可逆修改的定量比较用于深入了解驱动现场地震响应的机制。确定了六个可能的机制，包括三种温度驱动机制（裂缝开合的温度控制，表面应力条件和整体刚度），一种降水驱动机制（水渗透作用）和两种对温度和降水均敏感的机制（冰的形成和黏土行为）。合成了在气象约束下地震参数的可逆变化，并将其与在不同地质条件下发生破坏之前观察到的不可逆变化进行比较。