Download Homework Set 1

Geol 344: Earthquakes and Seismic Hazards
Spring 2006
Homework Set 1: Earthquake Locations, Magnitudes, and Depths
1. Using the USGS current earthquake information updates online (http:// earthquake.usgs.gov/
recenteqsww/Quakes/quakes_all.html), make a table of all earthquakes that have happened
so far in 2006 with magnitude greater than or equal to 6.0 (as of 1/19/06, there were at
least 6 such earthquakes). Note that earthquakes older than 7 days can be found using the
“Last 8-30 Days” link in the left column of the website.
Your list must be in chronological order. In your list, include the following information:
i)
ii)
iii)
iv)
(10)
date of earthquake in the local time zone
name of the epicenter geographic location (i.e., not lat/long)
magnitude
depth of focus
2. Describe the geographic distribution of the earthquakes in question 1. In what types of
tectonic environments did these earthquakes occur (divergent, convergent, or transform)?(10)
3. Go through the list of earthquakes that happened in January 2006 and make a frequency plot
(e.g. bar diagram or pie chart or line graph) of the number of earthquakes in different ranges
of magnitudes of earthquakes. You can do this by hand if you wish, but it would be much
easier to make the chart using a software program such as Excel. Divide up magnitudes into
the following ranges:
1) M<4
2) M4-5
3) M5-6
4) M>6
Once you have made the plot, write a few sentences describing the frequency of earthquakes
of different magnitudes, providing suggestions for the pattern you observe, including any
irregularities in the pattern. Possible useful guide:
http://neic.usgs.gov/neis/eqlists/eqstats.html
(20)
4. Again go through the list of earthquakes that happened in January 2005 and this time make a
frequency plot of the variation in depths of earthquakes. Divide up depths into the following
ranges:
5) 0-10km
6) 11-33km
7) 34-100km
8) 101-300km
9) 301-600km
10) > 600km
Your plot will thus show the number of earthquakes that occurred at each of these depths.
Once you have made the plot, write a few sentences describing the distribution of earthquake
depths, providing suggestions for why there was such a range of depths of earthquakes. (20)
Geol 344: Earthquakes and Seismic Hazards
Spring 2006
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