Geological Hazards and Their Impact_McGeary_Date_042310

Geological Hazards and Their Impact_McGeary_Date_042310 -...

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Iceland Eruption - divergent plate boundary - where the mid-ocean ridge has come up to the surface - almost all the magma is balsaltic - eruption on a fissure Characteristics of Stream Channels - begin at high elevations (source) - water flows downhill and usually ends at the ocean - stream profile (cross-section) stream is steeper closer to the source (flows faster) gradually decreases as you get closer to the ocean - the faster the river, the bigger the sediment particle size 2 types of streams 1) bedrock channel- carved into bedrock 2) “alluvial” channels- carved into sediment (sand, silt, clay) deposited by river itself “alluvial” plain flood plain - flood plains created by lateral erosion of the stream
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Unformatted text preview: • flat areas adjacent to steam channels, underlain by horizontal sediment layers deposited by stream • during floods, water overflows the channel and floods the flood plain ← ←- flooding occurs when water level in stream channel is higher than the stream’s banks • bankfull flow highest discharge or water level that can occur without flooding • levee walls of channel (riverbank) ← ←- What causes flooding? • Precipitation that flows (runs off) quickly into channels • Runoff occurs when more rain supplied than can infiltrate into the ground o Sandy and gravel soils lots of infiltration o Can’t infiltrate: clay soils, bedrock, frozen ground, already saturated ground, pavement ← ←...
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This note was uploaded on 08/30/2010 for the course GEOL 105 taught by Professor Kohut during the Spring '08 term at University of Delaware.

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