Page 454 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

THEhumanDENOMINATOR 13 Tectonics
TECTONIC PROCESSES HUMANS
• Earthquakes cause damage and human casualties; destruction is amplified in developing countries, such as Haiti.
• Volcanic eruptions can devastate human population centres, disrupt human transportation, and affect global climate.
HUMANS TECTONIC PROCESSES
• Human activity such as subsurface fluid injections associated with gas drilling can cause earthquakes.
13b
In 2012, the government approved exploratory shale gas drilling in Great Britain, despite environmental concerns. Recent research has linked oil and gas injection wells to increased earthquake activity in several U.S. states. [Christopher Furlong/Getty Images.]
13a
In 1959, an M 7.5 earthquake hit the area near West Yellowstone, Montana, fracturing highways along the shores of Hebgen Lake. This quake caused a landslide that dammed the Madison River, discussed in Chapter 14. [USGS.]
13c
13d
A scientist at the Hawaiian Volcano Observatory takes a sample of lava at Kīlauea, part of an effort to understand changes in lava chemistry on Mauna Loa. [USGS.]
Mexico’s Popocatépetl is an active composite volcano located about 70 km from Mexico City. Ongoing activity since
1994 includes growth of the lava dome within the crater, episodic steaming and ash emission, and ejection of material. Evacuation routes and shelters are ready for another eruption, which could affect millions of people living nearby.
[Violeta Schmidt/Reuters.]
ISSUES FOR THE 21ST CENTURY
• Growing human population centres in regions prone to seismic activity and near active volcanoes will increase the hazard.
• Scientific research is needed for earthquake prediction and volcano forecasting.
geosystemsconnection
Chapter 13 completes our study of Earth’s endogenic system with a look at the processes that build continental crust and create Earth’s topography. Mountain building, earthquakes, and volcanism are the outputs of this system, which is powered by radioactive decay in the planet’s interior. We focus in the next four chapters on the exogenic system, where solar energy and gravity empower weather- ing, erosion, and transportation of material by gravity, water, wind, waves, and ice—these are the processes that reduce landscape relief.
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