ESC102- volcanoes 1

pompeii

city in 79AD buried by mount Vesuvius

volcanoes

location where molten rock flows or erupts onto earths surface as lava

can happen on land or underwater

anatomy of a volcano (list)

magma chamber, pyroclastic material, conduit, central vent, crater, flank eruption, lava flows, volcanic debris

craters to calderas

eruption drains magma chamber

collapses into chamber

basin formed (caldera)

activity resumes as new volcano

gases produced by eruptions

water vapor, CO2, SO2, H2S

lava produced by volcanic eruptions

flows depending on silica and gas it contains

magma viscosity

depends on temperature, composition and volatile content

runny magma flows further

low silica, runnier. high volatile, runnier.

dome of lava

bulge formed by very viscous lava. inhibits flow of long distances before it solidifies.

A'a

sharp, spiny surface, basaltic deposit of high viscocity

pahoehoe lava

basaltic flow. low viscocity

types of lava structures

a'a, pahoehoe, pillow lavas, columnar basalts, pyroclastics

tephra

loose igneous material ejected from a volcano

pyroclast

infividual particles and classified according to size

types of pyroclastics

volcanic ash (<2mm), lapilli (2-64mm), peles hair, blocks/bombs (>64mm)