| A | B |
|---|
| Volcanism | processes which lead to the extrusion of lava, gases, and pyroclastic materials onto the surface and into the atmosphere |
| Active volcanoes | erupted during human history |
| Dormant volcanoes | no recorded eruptions, but still potential for eruptions |
| Extinct Volcanoes | no activity |
| Pyroclastic | flow deposit, fire fragments |
| Lava Flows | paths are predictable, rarely a danger to human life, |
| Hawaiian Lava Flows | pahoehoe and aa |
| Columnar Joint | lava flow that occurs in cooling lavas |
| Pillow lava | bulbous masses of basalt, resembling pillows, formed when lava is rapidly chilled under water |
| Pyroclastic Materials | deposited as solid fragments of explosive volcanism (ash,lapilli,bomb,block) |
| Volcano | conical mountains formed around a vent where lava,gases,and pyroclastic materials are erupted |
| Caldera | form when an emptied magma chamber collapses |
| Shield Volcano | low, rounded profiles, composed of numerous flows of mafic comp and little explosive activity, largest of all volcanoes |
| Cinder Cones | composed of pyroclastic materials that accumulate around the vent; steep slopes, usually short lived and map represent final eruptive stages |
| Composite Volcanoes | aka stratovolcanoes, composed of alternating layers of pyroclastics and lava flows, andesite common,eruptions infrequnt, violent and may involve lahars |
| Lava Dome | high-velocity, felsic magmas move slowly upward to form steep-sided lava domes |
| Nuee Ardente | dense cloud of pyroclastic material and gases; move down slope very rapidly |
| Fissure Eruptions and Basalt Plateaus | low viscosity, mafic lavas spread out and built up a basalt plateau |
| Low viscosity | not resistant to flow;spreads easily |
| Pyroclastic Sheet Deposits | cover large areas with felsic ash and welded tuff; appear to issue from fissures associated with caldera formation |
| Volcanic Explosive Index (VEI) | how eruptions are ranked from 0 to 8 based on volume of material explosively ejected, height of eruption plume |
| Volcano Monitoring | tiltmeters, seismic activity, past history, changes in magnetic and electrical fields, gas emissions, groundwater level and temp |
| Basalt and Gabbro | ocean crust is primarily _____ and ______. |
| Divergent Plate Boundaries and Igneous Activity | Mid-Atlantic Ridge, East Pacific Rise, Indian Ridge |
| Basalt | extrusive ocean crust on the surface |
| Gabbro | intrusive ocean crust on the sub-surface |
| Composite Volcanoes | found in the circum-Pacific and Mediterranean belts where partial melting produces intermediate/felsic magmas,lava domes,and violent eruptions. |
| Intraplate Volcanism | Occurs as a plate moves over a stationary 'hot spot' in the upper mantle |
