Monitoraggio del vulcano attivo Sakurajima (Giappone) con dati SAR satellitari: dalla misura degli spostamenti alla modellazione e previsione dell'evoluzione

The aim of this study is to validate the suitability of SAR Interferometric Time Series analysis based on several sensors and datasets for the monitoring of Sakurajima volcanic activity and the potential of defining adequate geophysical modelling leading to an operational forecasting tool. Sakurajima volcano is located inside Kagoshima Bay, Japan, on the southern rim of the Aira caldera. The volcano is known for its irregular explosions, typically 12 a day, of Strombolian or Vulcanian type which often produce very high eruptive columns (over 4 km). Studies on the supply of the system and its behavior observations indicate the presence of a large magma chamber under the Aira caldera at an approximate depth of 10 km. Additionally, a more superficial reservoir would be located under the central cone of the volcano. The recent activity of Sakurajima is particularly prominent. Several eruptions were registered in the last years, for example in 2016 a powerful eruption occurred on July 25th and in 2015 a rapid dike intrusion occurred on August 15th which generated strong deformations. In this study the activity of Sakurajima volcano is defined through interferometric analysis of SAR data (ALOS Palsar-2, COSMO-SkyMed and Sentinel-1) to obtain the caldera displacement over the observed period, between November 2014 and March 2018. Displacement evolution is derived to investigate its correlation with eruptions and diking. The Time Series, calibrated through Global Navigation Satellite System (GNSS) measurements, are used to identify the most dramatic events affecting Sakurajima area since 2015. Moreover, modeling of the rapid intrusion occurred in August 2015 and the eruption in July 2016 through Okada (1985) and Mogi (1958) models are presented