ARE EARTHQUAKES TRIGGERED BY HYDRAULIC FRACTURING MORE COMMON THAN PREVIOUSLY RECOGNIZED?

Felt earthquakes and earthquakes larger than microseismic seismicity common in hydraulic fracturing have become recognized in more places globally. Recent work suggests that earthquakes triggered by hydraulic fracturing may be more common than previously recognized in Oklahoma and suggest that this occurrence is more common elsewhere. This raises the questions of whether the occurrence is more common or simply that recognition has increased. Whatever the cause of the increased identification of earthquakes triggered by hydraulic fracturing, the identification and research of these cases can provide virtual observatories in different geologic settings for studying triggered seismicity from fluid injection. It is generally thought that waste-water disposal wells pose the greatest hazard from injection induced seismicity, and while this may be true disposal wells generally have limited amounts of geotechnical data available. In contrast production wells that have been hydraulic fractured often have much more geotechnical information available and provide constraints to the processes and properties of the subsurface. Cases identified from hydraulic fracturing will be used to demonstrate initial efforts of virtual observatories for induced seismicity.