Each eruption produces a layer of ash, lapilli or bombs which eventually lithifies (turns to rock) to form tuff or volcanic breccia.
(Each eruption; produces; a layer of ash, lapilli or bombs) (bombs; lithifies; to form tuff or volcanic breccia; T:eventually)
Each eruption bombs
produces lithifies
a layer of ash, lapilli or bombs
to form tuff or volcanic breccia T:eventually