Within the framework of precursor events related to earthquakes, this paper analyzes the possible effect on the aquatic environment of the surrounding energy that accompanies earthquakes, particularly in the area where oceanic and continental plates collide (Cocos Plate and North American Plate, south of Mexico). As a preamble, the types of precursor events, characteristics, and their possible origin are described. A project was designed under the assumption that in areas with high frequency and intensity seismicity there is an electrical and electromagnetic potential promoter which is detectable and assessable indirectly by measuring water conductivity behavior, which also may have atypical variations of data; the outcome of intensive conductivity monitoring in different settings, natural as well as manmade (wellsprings, artesian well and a cistern), are presented herein. The results of the conductivity monitoring for seven months, highlight two patterns in data behavior: one pattern shows the subtle dependence of data behavior on the geographic location of data monitoring instruments, revealing that could have a slight relationship between areas with increased seismic frequency and intensity and the presence of atypical conductivity variations. Another pattern reveals the possible relationship between atypical variations in conductivity and subsequent earthquake events; a total of 241 seismic events were analyzed and 59 of them are provided as evidence related with patterns mentioned.

Near faults or unstable areas where an earthquake could happen with capacity to damage buildings or infrastructure, there is often a previous energy that wanders around surroundings, this energy regularly is associated with electromagnetic emissions that generate an electric potential frequently studied as very, ultra-low and extreme frequency emissions (VLF-ULF-ELF_ EM) by remote sensing; under the assumption that this natural potential exists, in aquatic environment within the micro-seismic active area in the coastal border of Guerrero and Oaxaca estates, Mexico, an intensive conductivity monitoring in two artesian well was carried out. The results of intensive conductivity (µS/cm) monitoring done since March to July of 2015, using a low-cost Data logger sensor are presented. The results obtained of the study of 235 seismic events show that 61.64% of them manifest prior conductivity oscillation versus 38.36% of early conductivity oscillation, the possible origin of such oscillation and the likely relation with underground water recharge flux, ground light compression, ground tilt, local electromagnetic energy emissions, human interaction, was debated. The data analysis for long periods of conductivity monitoring and seismic events show that when the number of seismic events becomes intense, conductivity decreases and vice versa, resulting large fluctuations that grow over time like waves; within the study area a possible previous fluctuated long-term energy associated with earthquakes produced around could be arising.