The island of Ischia, located in the Gulf of Naples, represents an unusual case of resurgent caldera where small-to-moderate magnitude volcano-tectonic earthquakes generate large damage and catastrophic effects, as in the case of 4 March 1881 (I_max-VIII-IXMCS) and 28 July 1883 (I_max X-XI MCS) historical earthquakes, and of the recent 21 August 2017 MW = 3.9, event. All these earthquakes struck the northern area of the island. With about 65,000 inhabitants, Ischia is a popular touristic destination for thermals baths, hosting more than 3,000,000 visitors per year, thus representing a high seismic risk area. Assessing its seismic potential appears a fundamental goal and, to this end, the estimate of the magnitude of significant historical events and the characterization of their source are crucial. We report here a reassessment of historical data of damage of 1881 and 1883 earthquakes to evaluate the main source parameters of these events (obtained with the BOXER and EXISM software) and quantitatively compare, for the first time, the results with the source characteristics, obtained from instrumental data, of the recent 2017 earthquake. The results allowed us to assess the location, as well as the possible dimension and the related maximum magnitude, of the seismogenic structure responsible for such damaging earthquakes. Our results also provide an additional framework to define the mechanisms leading to earthquakes associated with the dynamics of calderas.

位于那不勒斯湾的伊斯基亚岛代表破火山口的不寻常情况，在该情况下，中小规模的火山构造地震会产生大的破坏和灾难性后果，例如1881年3月4日（I _max -VIII -IXMCS）和1883年7月28日（I _maxX-XI MCS）历史地震，以及最近发生的2017年8月21日MW = 3.9事件。所有这些地震袭击了该岛的北部地区。伊斯基亚（Ischia）大约有65,000名居民，是温泉浴场的热门旅游目的地，每年接待超过3,000,000名游客，因此是地震危险性高的地区。评估其地震潜力似乎是一个基本目标，为此，重要历史事件的大小估计及其来源的表征至关重要。我们在此报告对1881年和1883年地震破坏的历史数据的重新评估，以评估这些事件的主要震源参数（通过BOXER和EXISM软件获得），并首次将所得震源特征与结果进行定量比较。根据仪器数据 最近的2017年地震 结果使我们能够评估造成此类破坏性地震的震源结构的位置以及可能的尺寸和相关的最大震级。我们的研究结果还提供了一个额外的框架，用于定义导致与破火山口动力学相关的地震的机制。