The assessment of rockfall failure hazard in both spatial and temporal components is a critical task for risk assessment since it must rely on a complete and detailed inventory. Recently, rockfall hazard evaluation has often been carried out leveraging Terrestrial Laser Scanning (TLS) and drone-based photogrammetry for accurate rockfall detection. However, these techniques are time-consuming and costly, thus affecting the possibility of obtaining high temporal-resolution data. In this framework, Photomonitoring is emerging as a new technology that uses digital images captured by optical sensors to automatically measure changes and displacements, reducing human effort and economic expenses while increasing the data acquisition frequency. In this study, we installed a remote 4G camera at the Poggio Baldi natural laboratory, monitoring the rock slope by regularly capturing photographs for 396 consecutive days. The automatic image processing pipeline, integrated with a 3D model of the slope, resulted in a multi-temporal rockfall inventory enriched by several attributes, such as the date and location of occurrence, magnitude estimation, and involved lithology. By exploiting these features, the spatiotemporal distribution of rockfalls was investigated using descriptive statistics, geospatial analysis, failure probability, and cumulative frequency-magnitude relationship. Accordingly, the analysis of the slope activity rate combined with cumulative frequency-magnitude relationships outlined the local influence of lithology and pelitic-arenaceous ratio in rockfall failure hazard.

中文翻译：

---

落石破坏危险时空评估的自动光电监测分析


落石破坏危害的空间和时间分量评估是风险评估的一项关键任务，因为它必须依赖于完整而详细的清单。最近，落石危险评估通常利用地面激光扫描（TLS）和基于无人机的摄影测量来进行准确的落石检测。然而，这些技术既耗时又昂贵，从而影响了获得高时间分辨率数据的可能性。在此框架下，光电监测作为一项新兴技术，利用光学传感器捕获的数字图像自动测量变化和位移，减少人力和经济支出，同时提高数据采集频率。在这项研究中，我们在Poggio Baldi自然实验室安装了远程4G摄像头，通过连续396天定期拍摄照片来监测岩石斜坡。自动图像处理流程与斜坡的 3D 模型集成，生成了包含多个属性的多时相落石清单，例如发生日期和位置、震级估计和涉及的岩性。通过利用这些特征，利用描述性统计、地理空间分析、失效概率和累积频率-幅度关系来研究落石的时空分布。因此，边坡活动率结合累积频率-幅度关系的分析概述了岩性和泥质砂质比对落石破坏危险的局部影响。