Tephra from the 1979 Soufriere Explosive Eruption

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Science  04 Jun 1982:
Vol. 216, Issue 4550, pp. 1106-1108
DOI: 10.1126/science.216.4550.1106


The explosive phase of the 1979 Soufriere eruption produced 37.5 x 106 cubic meters (dense-rock equivalent) of tephra, consisting of about 40 percent juvenile basaltic andesite and 60 percent of a nonjuvenile component derived from the fragmentation of the 1971-1972 lava island during phreatomagmatic explosions. The unusually fine grain size, poor sorting, and bimodality of the land deposit are attributed to particle aggregation and the formation of accretionary lapilli in a wet eruption column.