Blasting and other mining-related activities in Kentucky: A source of earthquake misidentification

A review of seismograms from the University of Kentucky (UK) seismic network for the years 1984 through 1999 revealed that 46% of the identifiable events listed as earthquakes in national and regional catalogs for the Kentucky area were, in fact, blasts or other mining-related phenomena. Of the 109 events listed in the catalogs for the area considered, we were able to identify 39 as earthquakes, 27 as blasts, 6 as known roof falls, 5 as either an earthquake or blast (we disagreed as to which), and 32 events as inconclusive on the UK seismograms. The extent of the misidentification of blasts calls into question the reliability of such catalogs which include regions that lie outside of the seismic network used as the primary source of data for the catalog and in which there is mining activity. Inclusion of blasts and other miningrelated disturbances in the earthquake catalog for Kentucky could result in a mistaken estimate of the rate of seismicity and, consequently, the seismic hazard for the state.