Very long-period tremors (VLP)) have been observed in active volcanoes since the pioneering work by Sassa (1935) on supervolcano Asosan in Japan. These VLPs are are often considered as a diagnostic indication of fluid and gas motion inside the volcanic conduit (e.g., Kawakatsu et al, 2000; Chouet & Matoza, 2013). However, can VLP provide a useful inference on the state of physical-chemical processes and fluid motion inside active volcanoes (Gonnermann and Manga, 2007), such as magma ascent rate, and the volume and style of upcoming eruptions? This project aims at detection/characterization of VLP in active volcanoes through analysis of multi-years continuous seismic and tiltmeter data. In particular, the project will examine the source properties of VLP and infer temporal variations of magma/gas ascent rate over single or/and multiple eruption cycles. We also aim to develop a modelling scheme to use VLP to infer change in conduit plug/wall permeability.