HAWAII NATURE NOTES
Aalava with rough clinkery surface.
Andesitea lava generally of lighter color than basalt and richer in silicon and sodium.
Ashfine-grained volcanic ejecta, of sand or dust size.
Augitea variety of the mineral pyroxene containing aluminum.
Basalta dark heavy lava rich in iron and magnesium and comparatively poor in silicon; the common lava of Hawaii.
Blocksvolcanic ejecta larger than 1-1/2 inches across, solid when thrown out.
Bombsvolcanic ejecta, molten when thrown out, larger than 1-1/2 inches across.
Calderaa large depression formed by sinking in of part of the mountain top.
Cinder conea cone-shaped hill built by ejecta around a volcanic vent.
Cratera bowl-shaped depression, generally in the top of a volcanic cone.
Dikea sheetlike body formed by molten rock soldifying in a crack.
Ejectafragments thrown out by volcanic explosion.
Epicenterthe point on the earth's surface directly above the place of origin of an earthquake.
Epimagmaa semisolid lava resembling aa in appearance.
Faulta fracture in the earth's crust along which one side has moved with respect to the other.
Fault scarpa cliff formed by movement on a fault.
Feldspara light-colored mineral composed largely of silicon, oxygen, aluminum, and varying proportions of calcium, sodium, and potassium.
Fumarolea hole from which volcanic gases issue.
Igneous rocksrocks formed by solidification of molten rock.
Intrusive rocka rock formed by magma solidifying beneath the earth's surface.
Kipukaan "island" of old land left within a lava flow.
Lavahot liquid rock at or close to the earth's surface, and its solidified products.
Magmahot liquid rock.
Lapillivolcanic ejecta from about 1/4 to 1-1/2 inches across.
Olivinea green mineral composed largely of silicon, iron, magnesium, and oxygen.
Pahoehoelava with smooth or ropy surface.
Pele's hairvolcanic glass spun out into hairlike form.
Pele's tearscongealed lava droplets.
Phreaticresulting from ground water, like the steam explosions of Kilauea in 1924.
Pigeonitea pyroxene resembling augite but containing more iron.
Pisolitein volcanology, a small mud-ball, generally about the size of a pea, formed by raindrops falling through a cloud of volcanic ash.
Pit cratera crater formed by sinking in of the surface; not primarily a vent for lava.
Plagioclasea feldspar containing lime and soda but little potash.
Pumicea froth of volcanic glass.
Pyromagmaa fluid highly gas-charged very hot lava.
Pyroxenea group of dark-colored minerals composed largely of silicon, magnesium, iron, and oxygen.
Rifta fracture in the earth's crust.
Rift zonesthe highly fractured belts on flanks of volcanoes along which most of the eruptions take place.
Scoriaslaggy porous ejecta.
Shield volcanoa volcano having the shape of a very broad, gently sloping dome.
Solfataraa fumarole liberating sulfur-bearing gas.
Spatter conea cone built by spattery ejecta around a vent.
Talusrock fragments that accumulate in a heap at the foot of a cliff.
Ventau opening where volcanic material reaches the surface.
Vesicularhaving bubble-holes formed by gases.
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