SO262, Fall 2012
In Class Exercise--Volcanoes and Earthquakes
We have a number of data sets, some in several versions that allow different manipulation in Google Earth. You should be careful about loading all of them, as Google Earth may not be very responsive if you try to display them all at the same time.
USGS Plate Boundaries. Extracted from the KML displays of current seismic activity at USGS which credited the boundaries to Peter Bird of UCLA.
USGS Quaternary (< 1.6 MA) faults of the western US: (originally from USGS). They are sorted by age categories.
Smithsonian volcano database. This sorts volcanoes into stratovolcanoes, shield volcanoes, and others. There is another version on the web which has pictures of each volcano, and a description.
|Megathrusts. These come from USGS. They show all the earthquakes around one of the megathrusts, in both time and location.||Sorted by Magnitude|
|CMT earthquake catalog. This indicates both the type of fault, and the magnitude using a slightly different scale than in the USGS catalog above.||Earthquake focal mechanisms. This sorts the earthquakes into thrusts, normal faults, and strike slip faults. There are also oblique faults, with a combination motion. The types are differentiated by the stylized beach balls and colors. Particularly for smaller earthquakes far from land and seismic stations, the locations may only be approximate.|
|MB Magnitudes. This uses MB, one of several magnitude scales used by hard core seismologists. Particularly for the very rare, very large events, it is very hard to have a single scale which also works well for the much more frequent smaller events and the true monsters. You will note there are minor differences between these magnitudes and those in the megathrust data above.|
This is individual effort. You are to answer two of the following 5 questions in a Word document. For each, you should have several maps to support your answers to the questions. It will be due before class next week.
|Option 1.||Look at the Mid Atlantic Ridge. The plate boundaries have several
colors (mainly blue, green, and red) and no legend (but in the table of
contents you will see something which explains them).
|Option 2.||Look at the earthquakes in the time periods of the three megathrusts
of the last decade.
|Option 3.||Look at the Big Island of Hawaii, and the Cascade volcanoes in
Oregon and Washington. Include the USGS Quaternary faults.
|Option 4.||Look at the Great Basin in the Western US (the state of Nevada,
eastern California, and western Utah).
|Option 5.||Look at the East African Rift running SW from Ethiopia past Lake
Victoria to Lake Malawi.