ifice ▁and ▁the ▁w ides p read ▁v ents ▁may ▁reflect ▁the ▁interaction ▁between ▁the ▁vol cano ▁and ▁the ▁Li qui ñ e - Of qui ▁fault , ▁which ▁generated ▁fault - control led ▁secondary ▁v ents . ▁ ▁A ▁number ▁of ▁er u ption ▁products ▁show ▁traces ▁of ▁ice - lava ▁interactions . ▁A ▁geom agnet ic ▁anom aly ▁at ▁shall ow ▁depth ▁south ▁of ▁the ▁vol cano ▁may ▁be ▁a ▁plut on ▁associated ▁with ▁a ▁res urg ent ▁d ome . ▁Hu il il co ▁sc oria ▁cone ▁has ▁produced ▁two ▁la va ▁flows ▁and ▁is ▁considered ▁to ▁be ▁also ▁part ▁of ▁the ▁Qu et rup ill án ▁vol can ic ▁complex . ▁ ▁Three ▁different ▁form ations ▁make ▁up ▁the ▁bas ement ▁of ▁Qu et rup ill án : ▁The ▁Tri ass ic ▁P angu ip ul li , ▁the ▁possibly ▁C ret ace ous ▁Cur ra reh ue ▁and ▁the ▁Mi oc ene ▁Tr á pat rap a ▁form ations ▁and ▁plut onic ▁rocks . ▁These ▁are ▁plut onic ▁and ▁vol can ic last ic ▁rock ▁units . ▁ ▁Com position ▁▁ ▁Vol can ic ▁rocks ▁at ▁Qu et rup ill án ▁have ▁a ▁b im od al ▁composition , ▁r anging ▁from ▁bas alt ▁to ▁and es ite , ▁and ▁overall ▁more ▁sil ic ic ▁than ▁the ▁rocks ▁er upt ed ▁by ▁Vill arr ica ▁and ▁Lan ín . ▁Un us ually ▁for ▁the ▁region , ▁tra ch yd ac ite ▁also ▁occurs ▁at ▁the ▁vol cano .