The basement is cut by faults and lineaments such as the Pampacolca Fault on the southern side of the volcano and the Pumaranra and Cerro Casulla lineaments, which trend southeast-northwest and northeast-southwest, respectively. One east-west lineament may have influenced the recent volcanism; the alignment of Coropuna with Sara Sara, Solimana and El Misti may indicate a tectonic control on the volcano in general. On the southern flank, Holocene normal faults have offset lava flows and streams.