Possible mechanisms of magma redistribution under Mt Etna during the 1994-1999 period detected through microgravity measurements

摘要: SUMMARY We analyse a microgravity data set acquired along the Etna network and spanning 5 year long period (1994‐1999). The main feature observed is complete gravity increase (1994‐ 1996)‐decrease (1997‐1999) cycle mainly affecting southeastern sector of volcano reaching maximum amplitude approximately 100 µGal peak-to-peak. changes are principally due not to elevation but rather direct gravitational effect magma accumulation drainage below volcanic pile. In particular, mass increase‐decrease took place within 2‐4 km bsl deep reservoir that elongated, oriented NNW‐SSE, lies in volcano. accounts for volume ranging between 3 10 × 8 m , which believed have passed through inferred 1994 1999. Since most this has been erupted nor accumulated at shallower levels (at summit stations compatible observed), it could recycled by plumbing system, sinking down level deeper than source.