Question | Answer |
Asthenosphere | plastic like layer of Earth where the lithospheric plates float & move |
Cinder Cone Volcano | steep-sided, lossely packed volcano formed when tephra falls to ground |
Composite Volcano | volcano built by alternating explosive and quiet eruptions that produce layers of tephra & lava |
Continental Drift | Wegner's hypothesis that all continents were once connected in a single large landmass the broke apart about 200 million years ago and drifted slowly to their current positions |
Convection Current | current in Earth's mantle that transfers heat in Earth's interior and is the driving force for plate tectonics |
Crater | steep-walled depression around a volcano's vent |
Earthquake | vibrations produced when rock breaks along a fault |
Epicenter | point on Earth's surface directly above an earthquake's focus |
Hot Spot | result of an unusually hot area at the boundary between Earth's mantle and core that forms volcanoes when melted rock is forced upward and breaks through the crust |
Lithosphere | rigid layer of Earth about 100 km thick, made of the crust and a part of the upper mantle |
Pangea | large, ancient landmass that was composed of all the continents joined together |
Plate | a large section of Earth's oceanic crust and upper mantle are broken into plates that float and move around on a plasticlike layer of the mantle |
Plate Tectonics | theory that Earth's crust and upper mantle are broken into plates that float and move around on a plasticlilke layer of the mantle |
Primary Waves | seismic waves that move rock particles back-and-forth in the same direction that the wave travles |
Seafloor Spreading | Hess's theory that new seafloor is formed when magma is forced upward toward the surface at a mid-ocean ridge |
Secondary Waves | seismic waves that move rock particles at right angles to the direction of the wave |
Seismograph | instrument used to register earthquake waves and record the time that each arrived |
Sheild Volcano | broad, gently sloping volcano formed by quiet eruptions of basaltic lava |
Surface Waves | seismic waves that move rock particles up-and-down in a backward rolling motion and side-to-side in a swaying motion |
Tephra | Bits of rock or solidified lava dropped from the air during an explosive volcanic eruption |
Vent | opening where magma is forced up and flows out onto Earth's surface as lava, forming a volcano |
Volcano | opening in Earth's surface that erupts sulfurous gases, ash, and lava |