Phreatic and hydrothermal eruptions are small energetic explosive events that generally have few to no precursors and represent a considerable hazard in tourist and urban areas. At the Campi Flegrei caldera, these events have occurred at the Solfatara volcano and have likely occurred at the nearby Pisciarelli site, where the most powerful hydrothermal phenomena are located. Here, increased hydrothermal activity has caused relevant morphological changes that has led local authorities to deny access to the site. Stratigraphic, structural, and geophysical investigations have allowed us to reconstruct the volcano‐tectonic setting of the area. In particular, we have recognized a fault system and related damage zones that act as the preferred pathway for hydrothermal fluids in the caldera. At the surface, these faults control the migration and/or accumulation of deep‐seated gases into the subsoil and the formation of fumaroles and mud pools. We have recognized two main fault systems with different ages that show variable displacements. The electrical anomalies identified by electrical resistivity tomography further highlight the main fault pattern and show the interplay between volcano‐tectonic structures and fluid circulation. Host rocks and fault zones may be involved in self‐sealing processes and/or rock failure phenomena capable of modifying the fluid pathways and establishing favorable conditions, leading to overpressure and/or rapid decompression of fluids and triggering an explosive event. Furthermore, stratigraphic mapping shows fossil mud pool sediments embedded in an old debris flow located above the modern hydrothermal system. This implies that they were at a higher elevation when they formed. The morphotectonic evolution and intense rock alterations in the area could promote further landslide episodes, producing debris‐flow deposits that can cover the active area and possibly trigger hydrothermal/phreatic events.

中文翻译：

---

意大利南部Campi Flegrei火山口Pisciarelli Fumarole田地的火山构造环境：对流体循环模式和危害情景的见解

潜水和热液喷发是小型的高能爆炸事件，通常很少甚至没有先兆，在旅游和城市地区构成相当大的危害。在Campi Flegrei火山口，这些事件发生在Solfatara火山中，很可能发生在附近的Pisciarelli地点，那里是最强大的热液现象所在地。在这里，热液活动的增加引起了相关的形态变化，导致地方当局拒绝进入该地点。地层，结构和地球物理研究使我们能够重建该地区的火山构造环境。特别是，我们已经认识到断层系统和相关的破坏带是破火山口中热液的首选路径。在表面上 这些断层控制着深层气体向地下的迁移和/或蓄积，并形成了富马mar和泥浆池。我们已经认识到两个具有不同年龄的主要断层系统，它们显示出不同的位移。通过电阻层析成像确定的电异常进一步突出了主要的断层样式，并显示了火山构造构造与流体循环之间的相互作用。基质岩石和断层带可能参与自密封过程和/或岩石破坏现象，这些现象会改变流体路径并建立有利条件，从而导致流体超压和/或快速减压，并引发爆炸事件。此外，地层图显示化石泥浆池沉积物埋藏在位于现代热液系统上方的旧泥石流中。这意味着它们形成时处于更高的高度。该地区的构造构造演化和强烈的岩石蚀变可能进一步加剧滑坡事件，产生泥石流沉积物，这些沉积物可以覆盖活动区域并可能引发水热/潜水事件。