On the link between Earth tides and volcanic degassing

摘要: Abstract. Long-term measurements of volcanic gas emissions conducted during the last decade suggest that under certain conditions magnitude or chemical composition exhibits periodic variations with a period of about 2 weeks. A possible cause such periodicity can be attributed to Earth tidal potential. The phenomenology link has been debated for long, but no quantitative model yet been proposed. aim of this paper is to elucidate whether causal between forcing and in degassing traced analytically. We the response simplified magmatic system local gravity variations derive periodical vertical magma displacement conduit with an amplitude 0.1–1 m, depending on geometry physical state of the system. find while tide-induced magma displacement presumably significant direct effect volatile solubility, differential flow across radial conduit profile may result increase bubble coalescence rate at depth of several kilometres by up several multiples 10 %. Because coalescence facilitates separation from thus enhances volatile degassing, we argue derived variation may propagate a manifestation varying behaviour. presented model provides first basic framework which establishes analytical understanding tides degassing.