Time‐averaged SO₂ fluxes of subduction‐zone volcanoes: Example of a 32‐year exhaustive survey for Japanese volcanoes

Abstract

[1] All available SO 2 flux data for 32 years of Japanese volcanoes, accounting for about 10% of the world's arc volcanoes, were compiled to evaluate the temporal variation of the flux of each volcano and to estimate the time-averaged SO 2 flux. The compiled data revealed that 6 volcanoes (Tokachi, Asama, Aso, Sakurajima, Satsuma-Iwojima, and Suwanosejima volcanoes) out of 17 significantly degassing volcanoes usually contributed more than 94% of the total flux. The time-averaged annual flux was 2.2 Tg a À1, which includes intense degassing of Miyakejima volcano after 2000, which raised the figure from 1.4 Tg a À1, indicating that a single huge emitter is capable of significantly skewing regional time-averaged degassing totals and indicating that the time-averaged flux assessments for infrequent huge emitters are important for accurate estimation. The regional SO 2 flux distribution in cumulative frequency-flux plot does not obey a power law distribution. It shows a roll-off curve bending at about 500 t d À1, implying that it is misleading to assume the power law distribution for estimation of the global flux. Because the contribution of the major degassing volcanoes including the six volcanoes and additional sporadically degassing volcanoes during eruptive and posteruptive periods to the total flux is more than 95%, measurement of all large flux volcanoes can approximate the global flux.

A decade of global volcanic SO2 emissions measured from space

“…4). We also find a clear ‘roll-off’ of the distribution at an SO 2 flux of ~500–600 t/d, remarkably similar to that found in the ground-based Japanese SO 2 flux data48. This important result shows that the distribution of volcanic SO 2 emissions on the scale of individual arcs can indeed mimic the global distribution, provided that large flux datasets are available from a range of source strengths (i.e., including very strong emitters such as Miyake-jima).…”

“…Examination of the frequency-flux relationship of volcanic SO 2 fluxes in Japan reveals that they do not fit a power law distribution48, as had been previously suggested for the global flux distribution49. A frequency-flux plot for the OMI-derived SO 2 emissions confirms that the global volcanic SO 2 sources also do not follow a power law distribution (Fig.…”

Budget of shallow magma plumbing system at Asama Volcano, Japan, revealed by ground deformation and volcanic gas studies

“…(a) Sulfur dioxide emission rates averaged over 6 months calculated using the data from Mori et al . [] and Ohwada et al . [].…”

Permeability-control on volcanic hydrothermal system: case study for Mt. Tokachidake, Japan, based on numerical simulation and field observation

“…Tokachidake until the 1962 eruption. The discharge of sulfur dioxide from crater 62-2 was 210 t day −1 on July 7, 2007 (Mori et al 2006) and 140 t day −1 in 2006 (Mori et al 2013). At geothermal fields, buildup of solid silica often reduces the permeability of pipelines and wellbores.…”