Each of these regions has a potentially high earthquake hazard.
1. In California
San Andreas Fault - http://en.wikipedia.org/wiki/San_Andreas_Fault
2. In Washington and Oregon
Cascadia Subduction Zone - http://en.wikipedia.org/wiki/Cascadia_subduction_zone
Seattle Fault - http://en.wikipedia.org/wiki/Seattle_Fault
3. In Utah and Idaho
Wasatch Fault - http://en.wikipedia.org/wiki/Wasatch_Fault
4. In the Midwest - Missouri, Arkansas, Tennessee, Kentucky
New Madrid Seismic Zone - http://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone
The following file has the distribution of earthquakes for our 5 key regions: http://www.users.miamioh.edu/brudzimr/classes/USA-earthquakes.kmz
Please note that some computers have trouble recognizing a .kmz Google Earth file and get it confused with a .zip file, and sometimes even rename it into a zip file when you download it. If the downloaded file doesn't open in Google Earth, you should try to right-click on the link in this question and choose Save As and make sure the filename ends in .kmz
When you open this file in Google Earth, you should find 5 folders, one for each of the following metropolitan areas:
1. San Francisco Bay area2. Los Angeles3. Seattle4. Salt Lake City5. MemphisEach folder includes at least one Wikipedia link about a key earthquake or fault (earthquake symbol) and a catalog of earthquakes over the last 50 years for that region. Remember, you can open the folder and click the checkbox next to each of these pieces of information to show or hide it.
ShakeMaps show predicted earthquake shaking intensities from hypothetical earthquakes which are based on historic earthquakes. The predicted shaking intensities are converted into a Mercalli Scale that uses roman numerals (I-XI) to indicate the level of shaking and anticipated damage. The information we used in our Assignment can be found in the following file in Google Earth: http://www.users.muohio.edu/brudzimr/classes/USAshakemaps.kmz
When you open this file, you should find 5 folders, one for each of the metropolitan areas we have examined: San Francisco Bay area, Los Angeles, Seattle, Salt Lake City, and Memphis. Each folder includes at least one ShakeMap. You can open the folder and click the checkbox next to each ShakeMap to show or hide it. The main reason to look at these hypothetical earthquake ShakeMaps is to examine the key information that city planners use when trying to evaluate earthquake risks in each city.
Make sure your "Borders and Labels" in Google Earth are checked on, so that you can see label cities. You can use the red dot labeled San Francisco as the marker for downtown.
The probability of an event is a useful way for scientists to assess the risk of a certain hazardous event. For example, it is useful to know the probability of an earthquake occurring in a particular location so that emergency officials can prepare develop appropriate building codes, etc.
Geologists study the location of faults, the frequency and magnitude of past earthquakes on those faults to quantify the probability of an earthquake happening in that area over a given length of time. Geologists assume that future earthquakes will likely occur where past earthquakes have occurred, and base this assumption on observations of earthquakes over many years. Here in the U.S., the United States Geological Survey has the official responsibility of producing these probabilities. We can examine their probabilities at the following website: http://www.users.muohio.edu/brudzimr/classes/eqprob
This website enables you to find the probability of an earthquake of a magnitude 7 earthquake occurring during different periods of time. To help you evaluate the earthquake hazards in the 5 cities we have been investigating, you would have downloaded the following Excel file and completed the blank areas of the table using the USGS website: http://www.users.muohio.edu/brudzimr/classes/eq.probability.xls
Hopefully you kept this file because it probably took you some time to complete this table.
The probability of large ground shaking is another way that geologists assess the hazard risk for a particular area. While the amount of ground shaking that occurs during an earthquake is certainly related to the amount of energy released from it, e.g. magnitude of an earthquake, it is also directly related to the type of surface material at a given location. These levels of ground shaking are used primarily for formulating building codes and for designing buildings.
Peak Ground Acceleration (PGA) maps estimate the intensity of ground shaking based on actual instrumental measurements of ground type. The PGA is different than the Mercalli Scale, which uses human observations. In our Assignment, we investigated maps that show a PGA of 2% chance ground motion exceedance within the next 50 years: http://www.users.muohio.edu/brudzimr/classes/PGA.usa.jpg
The peak ground acceleration (PGA) is measured as a percentage of ‘g,’ which is the earth’s gravitational acceleration of 9.8 m/s2. So, for example, the areas of the map which are green in color have a 2% chance of shaking 0.10 or 10% of g.
You can use "Command +" on a Mac or "Cntrl +" on a PC to zoom in on a map. It may also be useful to have Google Maps open, so you can use this as a reference for where a city is located.