Virginia Earthquake Magnitude 5.8 August 23, 2011

Introduction

     Earthquakes happen unexpectedly without warning, sometimes resulting in fatal disasters. Recently, a 9.0 magnitude earthquake hit Japan, causing a tsunami that brought injuries and deaths among thousands. California is awaiting another massive earthquake. Many believe that the time is past due since 1994 when a 6.7 magnitude hit in Northridge. It is essential to prepare with canned foods and plenty of water. Children in schools practice drills to cover their head with one hand and the other holding a leg under the table. The majority of residents in California and most of the West Coast are ready for an earthquake. However, what happens if there is an earthquake rattling the East Coast of the United States? Surprising, a 5.8 magnitude quake shook Virginia on Tuesday, August 23, 2011, at 17:51:04 (UTC). Now, it is important to note that unlike the West Coast, the continental crust at the East Coast is older, colder and denser. Therefore, shaking can transmit about three times the distance. The quake was centered in Louisa County where the North Anna Nuclear Power Station was shut down. Atlanta, Georgia to Illinois to Detroit, Michigan to New York felt it. Even President Obama felt it while playing golf on his vacation in Washington, DC. The East Coast was not ready for an earthquake. Various reactions are predictable: What happened? Is that an earthquake? BOMB! Terrorist Attack! Everyone evacuates the buildings and stand on the streets confused and shocked. Luckily, no severe injuries or deaths were reported. How many people did the Virginia earthquake affect? My goal is to show the population count according to specific distances from the epicenter. It is interesting that this quake was the most powerful earthquake to strike the East Coast in 67 years. This is definitely worth researching. On a side note, top Universities affected by the Virginia earthquake was also recorded just out of curiosity because I assume that if there is another earthquake in California anytime soon, I will most likely be in the UCLA campus.

Method

     In order to accomplish this project, it required many steps. First, I had to obtain data. Data searching was time consuming considering the fact that census tracts 2011 for the U.S. were not available for download. UCLA GIS had census tracts 2008 so I used this one instead since the tract polygons are consistent. The only problem was that this census tracts file was a SDC file. I had to convert the SDC file into a Geodatabase using Feature Class to Geodatabase (multiple) under To Geodatabase in Conversion Tools. The output had to be saved into a blank folder. An error popped up when saving it into a folder with existing files inside it. Converting the SDC file was necessary to allow editing the attribute table. The epicenter was found in USGS and formatted into an Excel sheet that was saved as a 93 version and exported into a single database through ArcCatalog. Then, the x and y coordinates were added as data in ArcGIS.

     After creating multiple buffers of 100 miles apart up to 500 miles from the epicenter, I selected by attributes. It was a repetitive process of selecting by attributes and selecting by location. The buffer layer of the epicenter was the layer in focus when selecting by attribute. Unique values were chosen for “FromBufDist” and “ToBufDist” separated by “AND” and using the “=” sign. For example, FromBufDist=0 AND ToBufDist=100, depending on what buffers to highlight. After the buffers are highlighted, Target Layer for selecting by location was the converted geodatabase file for census tracts. The source layer was the buffer layer of the epicenter and spatial selection method was target layer features are within the source layer feature. When clicking OK, the target layer features are selected on the map layout.

     Finally, we can start editing. I opened the census tracts attribute table and showed selected records. A new field was added and named. Field calculator was used to give an integer for the values selected. The next part is the easy part. Open census tracts properties and choose pop2007 under the symbology tab. Add all values. The Count column includes the total count according to the selected target layer features within the source layer feature but this is not the total population count. The population sum can be found under statistics in the attribute table. The column with the integers assigned can be changed to help show the exact number on the legend. This process was repeated for every 100 mile buffer distance. Colors representing each population within 100 mile buffers were adjusted and darkened to show clarity. A map with no field calculating is also included above just for reference purposes. Here, population size for each county can be generally determined within 100 mile buffer zones.

     The top Universities in the United States was found in U.S. News & World Report. Addresses for these Universities were gathered using Google Maps and individual University sites. The addresses were inputted into an Excel sheet and exported as a dbase through ArcCatalog. An address locator is not possible to make with the states file that was downloaded from UCLA GIS. Therefore, I used the default address locator provide in the Geocoding tool, which proved efficient. The same was done for the North Anna Nuclear Power Station, but in a separate Excel sheet. Since the purpose was to show the Universities affected within the 500 mile buffer, I selected by attributes using FromBufDist as 0 and ToBufDist as 500. Select by location with target layer as the Universities layer that was geocoded and the source layer as the buffer layer of the epicenter. Again, spatial selection method was target layer features are within the source layer feature. In the attribute table of the Universities layer, there is an option to export into a new table. Show selected records and export. Lastly, use the new table to create the report.

Results

     Although the earthquake was centered in Virginia, 100 miles from the epicenter had the least population count affected by the shake with a total count of only 7,942,887 people. The population count for 100 to 200 mile buffers was the second least at 16,300,404 people. The most population count affected by the shake was within 200 to 300 mile buffers. This area included parts of Pennsylvania, New Jersey, Ohio, New York, Kentucky, West Virginia, Virginia, Tennessee, North Carolina, and South Carolina with a total count of 34,504,956 people affected. It was also unique to find that areas within 300 to 400 mile buffers and 400 to 500 mile buffers had almost the same number of people affected by the earthquake. The count for 300 to 400 mile buffers was 27,028,910 people. The count for 400 to 500 mile buffers was 30,905,272 people. The total number of people affected within all buffers equal to 116,682,429 people. The counties in the color white represent the population of the whole United States outside of the buffers. It is important to note that this result only refers to the population affected in the U.S. within 500 miles of the epicenter. The news reports that Canada and as far as Greenwich at the south of London, England felt the quake.

     The earthquake affected more than half of the 100 top Universities from the US News & World Report. A total number of 55 Universities were affected within 500 miles of the epicenter. Also, it is evident that the North Anna Nuclear Power Station was extremely close to the epicenter. The University closest to the epicenter was University of Virginia in Charlottesville. Most of the Universities affected were situated along the East Coast of the US.

Discussion/Conclusion

     This project is purely based on statistics and data. It is not a real and definite presentation of the exact population count affected by the earthquake, but rather a reasonable estimate. The reason I state this is that the vibration of the earthquake predominately shook the East Coast of the United States. Also, there could be a number of people out of state for vacation or not present due to other reasons. Naming this project “A hypothetical approach to how many top Universities and people could have been affected by the Virginia earthquake, given that vibrations spread across evenly in all directions,” would be more accurate. However, the statistics and buffers given in these maps prove how devastating the earthquake could have been if the magnitude was higher. A lot of people could have been injured or dead. Nuclear power plants would be damaged and there would be another mayhem much like Japan's tsunami. The extent of how much of the total population possibly felt the earthquake is shown within the buffers. Obviously, the closest population and Universities from the epicenter felt it. Basically, the whole East Coast of the US had to have felt the quake. The rest is based on personal experiences and comments but I assume that the majority of the population felt it. It is interesting to know how far an earthquake can shake depending on where it is situated. I assume that grocery stores of the East Coast are selling water fast. Suddenly, the East Coast is preparing for what the West Coast has prepared for a long time.

References

Dominion. 2011. “North Anna Nuclear Information Center.” http://www.dom.com/about/stations/nuclear/north-anna/north-anna-nuclear-information-center.jsp

Google Maps. http://maps.google.com/maps?hl=en&tab=wl

Technica, Ars. Wired Science. 2011. “Why the East Coast Earthquake Was Felt So far Away.”

http://www.wired.com/wiredscience/2011/08/virginia-earthquake-distance/

UCLA GIS. http://gis.ats.ucla.edu/

U.S. Geological Survey. “Magnitude 5.8 – VIRGINIA.” http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/se082311a.php

US News & World Report. 2011. “National University Rankings.” http://colleges.usnews.rankingsandreviews.com/best-colleges/rankings/national-universities