lava cone - built by successive flows of lava from a central vent --> shield shaped volcano

-accumulation of lava flows

rhyloitic and andesitic lavas (more viscous) - bulbous, steep sided mass

-often plug vents and trap gasses

-pressure can build and blast dome into fragments

form from volcanic vents that discharge pyroclasts

-fragments from cinder cones

-concave accumulation of pyroclasts

-profile depends on angle of repose

volcanoes that emit lava and pyroclasts; alternating lava flows and blasts of pyroclasts build to concave shape

-strengthened by dikes and solidified lava in central feeder

-common above subduction zones

large, steep walled basin-shaped depression

-when a violent eruption empties a volcano's magma chamber which cant support rock

-collapse and leave flat basin

-may reinflate (resurgent caldera)

when magma from earth's interior escapes explosively, the vent and the feeder channel are often left filled with volcanic breccia as eruption wanes

-kimberlite pipes

peridite ultramafic rock left behind (diamond)

-come from deep within earth

-assoc with deeper diatremes

-largest eruptions; come from small, nearly vertical cracks in earth's surface (very long)

-basaltic lava; along mid ocean ridges wehere new oceanic crust forms

-flood basalts

-ash flow deposits

continuous flow of water heated and returned to surface by buried magma

hot water fountains that spout intermittently

volcanism at spreading centers

large volumes of basaltic lava erupt at mid ocean ranges (created sea floor)

-divergent boundaries - zig-zag pattern by transform faults

+short, parallel spreading centers

+axial volcanoes - spreading centers of parallel length

voncanic mountains lie parallel to convergent boundaries

(above sinking slab

-magmas made by fluid induced melting; varied in chem comp

-range from mafic to felsic (basaltic to rhyolitic;few intermediate)

-subduction volcanoes form as island arcs where lithos is oceanic

fissure eruptions release large amts of lava

flood basalts can be LIP's

-large volumes of mostly mafic extrusive and intrusive ig. rocks

-origins lie in processes other than seafloor spreading

-continental flood basalts, assoc. intrusive rocks, oceanic basalt plateaus, aseismic ridges

torrential flows of wet volcanic debris

-occur when pyroclastic flow meets river/snow; when wall of a water filled crater breaks; when lava flow meets glacier; when rain pushes ash into mud

volcanic mt. constructed from thousands of deposits of lava, or pyroclasts or both

-not very stable

-sides may break off

infrequent

earthquakes

carbon dioxide leaks