syneruptively

adverb1

1. •
   In a syneruptive manner; occurring during the time of a volcanic eruption.

   • Fig. 6. A block of feldspar-bearing sandstone which syneruptively subsided in the Rödern diatreme in the Carboniferous-Permian Saar-Nahe Basin, SW Germany (Lorenz 1971). — 1986