Review material for Exam #2 in GLG 112 Natural Disasters – Spring 2010
Exam #2 covers Chapter 4, Volcanoes; Chapter 6, Mass Wasting; and Chapter 7,
Subsidence and Soils.
Be sure to read the material in each chapter and carefully read the summaries.
Review slides in the presentations online at http://oak.ucc.nau.edu/dmb25.
For each chapter shown below, have an understanding of-Chapter 4:
The tectonic cycle as it relates to divergent and convergent plate boundaries;
examples of each of these types of boundaries; examples of major plates on earth;
where do volcanoes occur and what are their causes. What’s involved with hot spot
volcanism and know examples; the similarities in spatial occurrence of earthquakes
and volcanoes; two major types (central point and fissure) of volcanic eruptions with
specific volcano types that form and examples of each. The role that increasingly
complex silicate structures in magmas and lavas controls viscosity; the products of
volcanic activity and how gases contribute to the eruption process; characteristics of
basaltic, andesitic, and rhyolitic lava flows; how pillow basalts form; what constitutes
pyroclastic debris and how it is distributed around the source area; the variety of
volcanic gases; relative sizes of different volcanic features; what happened at Mount St.
Helens?; flood basalts—their causes and examples; what make up volcanic hazards; the
degree to which active volcanoes exist in the Pacific Northwest; examples of volcanic
types and their relative size; how geysers work; how volatiles, viscosity, and volume
change for the different types of volcanoes; what is a lahar; past eruptive history of Mt.
Rainier in terms of lahar flows.
Chapter 6:
Types of landslides
Slow vs rapid mass wasting [MW] and know examples of each
Forces operating on a mass resting on a sloped surface
How slope angle change affects the gradient [or slope]
Role that gravity, mineral composition and water play in MW
Three main causes of slope failure; driving vs. resisting forces
How slope gradient can affect hillsides
Difference between rotational and translational slides
Relative speeds and moisture content of different movements
Landslide problems at La Conchita, CA since 1995
How do we minimize MW hazards?
Chapter 7:
What is subsidence and its various causes?
Understand the basics of limestone erosion and features it forms
What does the introduction of water do to clay minerals?
What are desiccation cracks and how do they form?
How changes in the water table can cause subsidence.
What is karst topography?
What causes regional subsidence?
Areas in United States where karst is common
How do humans contribute to subsidence?