GEOL 106 Lecture 12: geol 106
15 May 2018
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3.7 Human Interaction with Earthquakes
- several human activities are known to increase or cause earthquake activity
EARTHQUAKES CAUSED BY HUMAN ACTIVITY
- 3 ways:
1. loadig Earth’s rust, as i uildig a da ad reservoir
2. injecting liquid waste deep into ground through disposal wells
3. creating underground nuclear explosions
WATER RESERVOIRS
- construction of large deep reservoir behind dam on river → may induce earthquakes
o weight of water can create or extend fractures in adjacent rock an increase water pressure in
surrounding groundwater → may produce new faults or lubricate and activate existing faults
- e.g. Hoover Dam and filling of Lake Mead in Arizona and Nevada → small quakes
DEEP WASTE DISPOSAL
- injecting fluids into Earth can cause earthquakes → increases underground fluid pressure and cause
slippage of numerous fractures in metamorphic rock
- high correlation between rate of waste injection and location and timing of earthquakes
- when injection of waste stopped so did the earthquakes
- studies suggest that high fluid pressures are present in many areas where earthquakes occur
- fluid pressure rises in area until rocks break → triggers earthquake and discharging fluid upward
o after event, fluid pressure begins to build up again → another cycle
NUCLEAR EXPLOSIONS
- underground tests of nuclear weapons in Nevada → triggered numerous earthquakes
o explosions may have released some natural strain within Earth
- nuclear explosions may be used to prevent large earthquakes by releasing strain before it reaches
critical point
o but release at one fault might trigger unanticipated earthquakes on other faults
find more resources at oneclass.com
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Document Summary
3. 7 human interaction with earthquakes several human activities are known to increase or cause earthquake activity. 3 ways: loadi(cid:374)g earth"s (cid:272)rust, as i(cid:374) (cid:271)uildi(cid:374)g a da(cid:373) a(cid:374)d reservoir injecting liquid waste deep into ground through disposal wells: creating underground nuclear explosions. Deep waste disposal injecting fluids into earth can cause earthquakes increases underground fluid pressure and cause slippage of numerous fractures in metamorphic rock. High correlation between rate of waste injection and location and timing of earthquakes. Underground tests of nuclear weapons in nevada triggered numerous earthquakes: explosions may have released some natural strain within earth.
