Shield volcanoes are formed by lava flows of low viscosity - lava that flows easily. Consequently, a volcanic mountain having a broad profile is built up over time by flow after flow of relatively fluid basaltic lava issuing from vents or fissures on the surface of the volcano.
S.H.I.E.L.D. is a fictional espionage, law-enforcement, and counter-terrorism agency appearing in American comic bookspublished by Marvel Comics. Created by Stan Lee, it often deals with paranormal and superhuman threats.
