Exam 5: Earthquakes Throughout the United States and Canada

Much of the San Francisco Marina District is built on artificial fill debris from the buildings ruined by the 1906 earthquake.Seismic waves in 1989 were ____________ in this artificial fill.

In historic time,Nevada has averaged one earthquake with a magnitude in the 6s per decade and one with a magnitude in the 7s every 27 years.

The large left step in the San Andreas fault in the Los Angeles area causes compressive ruptures along east-west-oriented ________ faults as in the 1971 San Fernando and 1994 Northridge events.

Aftershocks of the 1811-12 New Madrid,Missouri,earthquakes are still occurring today.

The Cascadia subduction zone is 750 miles long,and its characteristics of youthful oceanic plate and strong coupling with the overriding plate are similar to situations in southwestern Japan and southern Chile where very large earthquakes have occurred.

Failed rifts remain as zones of weakness that may be reactivated by later plate-tectonic stresses to once again generate earthquakes.

Common reasons for building failure in the World Series quake included poor connections of houses to their foundations,buildings made of un-reinforced masonry or brick-facade construction,and two- to-five-story buildings deficient in shear-bearing internal walls and supports.

The New Madrid and San Francisco earthquakes were of similar magnitudes,but the felt area of the New Madrid quakes was much smaller.

In the last 5.5 million years,rifting action has torn Baja California and California west of the San Andreas fault (including San Diego,Los Angeles,and Santa Cruz)from the ______________.

Earthquakes below Kilauea volcano are dominantly deep events in the mantle.

The zone of dangerous faults in Southern California is much wider than in the San Francisco Bay area,largely because the major plate-bounding fault (the San Andreas)is bent so far to the west that it makes it difficult for the Pacific plate to slide along on its northwestward journey.

New England has a long record of significant earthquakes.

Which of the following represents evidence for major fault movement on the Seattle fault zone about 1100 years ago?

The "creeping" section of the San Andreas fault between San Juan Bautista and Cholame has numerous earthquakes smaller than magnitude 6 that accommodate the plate-tectonic forces before they build to high levels.

On 28 October 1983,the Lost River fault broke free for a magnitude 7.3 MS event,moving Borah Peak,Idaho's highest point,0.3 m (1 foot)lower.

Much of Utah's population lives within sight of the scarps of the 230-mile-long Wasatch Front,the zone of reverse and strike-slip faults separating the mountains from the Great Basin.

In the 1989 Loma Prieta quake,the Marina District building collapses were extensive,and numerous destructive fires broke out,due to all but which one of the following?

Eastern U.S.damages may be experienced over a smaller area than they would be for an equivalent-sized earthquake in California.

Most North American earthquakes occur in the west along the edges of the active plates,but the central and eastern regions also have earthquakes-not as many but just as large.

On 9 January 1857,the San Andreas fault segment between Cholame and San Bernardino broke loose at its northwestern end,and the rupture propagated southeastward in the great ________ earthquake with a magnitude of about 8.3.