NOTE: EARTHQUAKE_EPICENTERS_IN of March 5, 2003, was updated on March 24, 2011.
<http://wwwneic.cr.usgs.gov/neis/epic/epic.html>
2) Saint Louis University, Department of Earth and Atmospheric Sciences
<http://www.eas.slu.edu/Earthquake_Center/earthquake_data.html>
3) Advanced National Seismic System (ANSS)
<http://www.ncedc.org/anss/catalog-search.html>
4) For earthquakes that occurred before 1954, magnitudes and locations of epicenters were compiled from newspaper articles or other anecdotal evidence and may have substantial errors. For earthquakes that occurred after 1954, magnitudes and locations of epicenters were determined using modern seismographs and are presumably more accurate.
This data set was compiled by Indiana University, Indiana Geological Survey, using data believed to be accurate; however, a degree of error is inherent in all data. This product is distributed "AS-IS" without warranties of any kind, either expressed or implied, including but not limited to warranties of suitability of a particular purpose or use. No attempt has been made in either the designed format or production of these data to define the limits or jurisdiction of any federal, state, or local government.
These data are intended for use only at the published scale or smaller and are for reference purposes only. They are not to be construed as a legal document or survey instrument. A detailed on-the-ground survey and historical analysis of a single site may differ from this data.
It is requested that the Indiana Geological Survey be cited in any products generated from this data. The following source citation should be included: [EARTHQUAKE_EPICENTERS_IN: Epicenters of Earthquakes in Indiana with a Magnitude Greater Than 3.0, Through 2010(Indiana Geological Survey, 1:3,500,000, Point Shapefile)]
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405-2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.
1) Completeness of values were verified
- No values were left blank, unless appropriate.
2) Validity of values were verified
- All features were attributed with values in the appropriate range and format.
Note regarding values of magnitude:
Prior to seismographic instrumentation, earthquake magnitudes were described in terms of the damage that they did or how the ground shaking was perceived by residents of the affected region. The Modified Mercalli Scale best fits verbal descriptions of earthquake induced ground motion. From Modified Mercalli Scale values, it is possible to estimate a highly generalized or most probable Richter magnitude for the event. For example, a Mercalli VII earthquake corresponds to a magnitude 4.6 to 5.8 earthquake. Estimating magnitudes from Mercalli values is difficult and the Richter values should be taken as only approximate estimates.
The "Catalog of Central United States Earthquakes Since 1800 of mb >3.0" was downloaded from the Saint Louis University website (file: "nuttli.zip"). The file "nuttli.zip" was uncompressed and imported into Microsoft Excel. This catalog includes all recorded quakes in the central U.S. for the period between 1800 and 1980. All records were extracted for earthquakes with epicenters located between 37 and 42 degrees north latitude and 84 and 89 degrees west longitude. Extracted records were copied to a new spreadsheet where several data fields were removed (hour, minute, felt area, epicent intensity, surface wave magnitude, and references).
Similarly, data from the U.S. Geological Survey's Earthquake Information System (NEIC) was downloaded based on a spatial query which specified the same geographic area as described above. This data from the USGS Preliminary Determination of Epicenters catalog included earthquakes occurring between January 1973 and December 2000. This data was copied from the Web browser to a text editing program (Notepad) and then imported into Microsoft Excel. Once in Excel, three fields were removed (Time, Depth, and DTSVNWG).
Data from the two Excel spreadsheets were then combined in a singe spreadsheet and exported to .dbf format to facilitate importation into ESRI ArcView GIS. The *.dbf file was converted to a point shapefile in ESRI ArcView (version 3.2 for Windows) using the "Add Event Theme" and "Convert to Shapefile" commands. Points were then projected to UTM Zone 16, NAD 83 using the "Projector!" extension in ESRI ArcView.
Using the "Edit" function in ESRI ArcMap, all points in the shapefile named "EARTHQUAKE_EPICENTERS_IN" that had a magnitude of less than 3.0 were deleted. Values in attributes related to date ("YEAR," "MONTH," and "DAY") were compared with corresponding date values in EARTHQUAKE_UPDATE_ANSS_UTM.SHP. Where values were equal, and where points were in close geographical proximity, the point in EARTHQUAKE_EPICENTERS_IN was deleted, while the corresponding point in EARTHQUAKE_UPDATE_ANSS_UTM was retained. Where points in EARTHQUAKE_EPICENTERS_IN were in exactly the same geographical location as points in EARTHQUAKE_UPDATE_ANSS_UTM, the points in EARTHQUAKE_EPICENTERS_IN were deleted, while the points in EARTHQUAKE_UPDATE_ANSS_UTM were retained.
Using the "Append" function in ESRI ArcToolbox, the shapefile named "EARTHQUAKE_UPDATE_ANSS_UTM.SHP" was combined with the shapefile named "EARTHQUAKE_EPICENTERS_IN.SHP" to produce a shapefile named "EARTHQUAKE_COMBO.SHP." Values in the field named "MAG" were copied into the field named "MAGNITUDE" using the "Field Calculator" function. In the field named "CAT," blank cell were populated with a value of "ANSS." Fields named "Magt" and "CAT" were deleted. Using ESRI ArcCatalog, EARTHQUAKE_COMBO.SHP was renamed "EARTHQUAKE_EPICENTERS_IN.SHP."
Magnitude is a number that characterizes the relative size of an earthquake. Magnitude is based on measurement of the maximum motion recorded by a seismograph sometimes for earthquake waves of a particular frequency), corrected for attenuation to a standardized distance. Several scales have been defined, but the most commonly used are
(1) local magnitude (ML), commonly referred to as "Richter magnitude,"
(2) surface-wave magnitude (Ms),
(3) body-wave magnitude (Mb), and
(4) moment magnitude (Mw).
Scales 1-3 have limited range and applicability and do not satisfactorily measure the size of the largest earthquakes. The moment magnitude (Mw) scale, based on the concept of seismic moment, is uniformly applicable to all sizes of earthquakes but is more difficult to compute than the other types. In principal, all magnitude scales could be cross calibrated to yield the same value for any given earthquake, but this expectation has proven to be only approximately true, thus the need to specify the magnitude type as well as its value.
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405-2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.