This paper examines the relationships between recent shallow
seismicity and exploitation of fluids in the northern Burgos Basin where
cumulative seismic events recorded in the State of Nuevo Leon reach a total of
304 earthquakes between 2006 and 2016. In detail, 2 to 5 yearly events occurred
from 2006 to 2011; but a later remarkable increase was evident as follows: 89
in 2012, 69 in 2013, 75 in 2014, 31 in 2015 and 27 in 2016. This behavior
doesn’t match the random fluctuations from natural seismicity rates. A
statistical analysis allowed us to determine that the sequence of earthquakes
after 2011 could be related to the activity of exploratory wells in the Burgos
Basin, which were drilled down to the Pimienta (Upper Jurassic) and Agua Nueva
(Upper Cretaceous) shale gas plays. The epicenters located in the State of
Nuevo Leon, in the municipalities of China, General Terán, Montemorelos and Los
Ramones, were associated with the Upper Jurassic Pimienta and Upper Cretaceous
Agua Nueva shale gas fields. Only 17 earthquakes had magnitudes ranging from
4.0 - 4.5 Richter magnitude and those were associated with the exploratory
wells Anhelido-1, Arbolero-1, Batial-1, Durian-1, Kernel-1, Mosquete-1,
Neritas-1, Nuncio-1, Serbal-1 and Tangram-1. The hypocenters correspond to the
depth at which the Pimienta and Agua Nueva Formations lie; hence, sharp changes
in the minor shock frequencies were considered as indicators of induced
seismicity related to hydraulic fracturing for fluid extraction. The
scatterplot of the frequency and magnitude of events for 2009-2014 shows slopes
between -7.0963 to -1.1538 that were considerably more negative than the
natural seismicity values which span from 0.75 to 0.9. The slopes for 2012,
2013 and 2014 are negatives (-7.0963, -0.3656 and -0.1333), respectively. These
dramatic changes in increasing of the minor shock sequences in the Burgos Basin
allow us to be considered as indicators of induced seismicity due to fluid
exploitation. This interpretation is based on the frequency and magnitude of
shocks which achieve values of hydraulic fracturing-induced earthquakes associated
with anthropogenic fracking, similar to other seismicity data obtained in
different parts of the world where this technique is applied.
Author(s) Details
Juan M. Rodríguez-Martínez Author(s) Details
Depto. de Geohidrología y Geofísica, Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, Monterrey, México.
Eduardo A. Rossello
Depto. Ciencias Geológicas, CONICET-Universidad de Buenos Aires, FCEN, Buenos Aires, Argentina
Dr. Arquímedes Cruz López
Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, México.
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