Author(s)

Marilia Hagen^1*, Anibal Azevedo²

¹Universidade Federal Fluminense, Instituto de Física, Niterói, Brazil.
²Faculdade de Ciências Aplicadas da Unicamp, Limeira, Brazil.

Since the 1950s, small tremors created by human actions have been catalogued and recorded by the USGS. However, there is no academic explanation of the mechanism involved in these quakes. The aim of this work is to show that the propagation of mechanical fractures created in certain areas is one factor responsible for triggering earthquakes. Technically, this fracturing process depends on the ratio between pressure and tension, i.e., Young’s modulus, and locally depends on the specific material under pressure. Examining the entire territory of the U.S., we were able to identify certain states where Griffith’s theory was applied to explain the results found in those states. This study works with public records available from USGS. Therefore, any classified event or information is outside of the scope of this paper. We also investigate mid-continent or intraplate earthquakes during the period 2000-2016 with magnitudes M2 to M3.8 in shallow depths that appear to be amplified in consonance with development by companies in fracking, oil-gas assessment, mining, quarry blasting, experimental explosions, and collapses. Of particular interest was the enhancement of earthquakes during 2000-2016 for events M ≥ 4 surrounding the Mississippi Lime near the Oklahoma/Kansas border. Overall, all the anthropogenic events could be elucidated by Griffith theory.

Anthropogenic, Intraplate Earthquakes, Griffith Theory, Young Modulus

Hagen, M. and Azevedo, A. (2017) Anthropogenic Enhancement of Earthquakes in the Conterminous USA. Journal of Geoscience and Environment Protection, 5, 69-87. doi: 10.4236/gep.2017.56009.