Effects of Earthquakes on Hydrothermal Vent Temperature and Resistivity at the Main Endeavor Field, Northeast Pacific

Abstract

Hydrothermal vents are important deep ocean structures that provides a necessary biogeochemical environment which supports life. The flux of high temperature vent fluid, via hydrothermal circulation, mixes with cooler ocean water and increases pH since vent fluid is acidic, which enables precipitation of important molecules like iron sulfide and manganese. The hydrothermal circulation process consists of seawater entering permeable fractures surrounding vents and reaching the reaction zone, just above the magma chamber in Layer 3 of the oceanic lithosphere, which is the lower section of the oceanic lithosphere and upper mantle. The interaction of seawater and magma adds Fe, Mg, Si, Al, Ca, S, and other elements to this fluid mixture. Once temperature and pressure reach a certain point in Layer 3, the fluid is be expelled back into the ocean and disseminates the newly formed elements into surrounding seawater. The addition of the elements then creates a habitable environment that supports life at the extreme depths where the vents form. The purpose of this research and analysis, was to determine whether earthquake activity affects hydrothermal vent temperature and resistivity in the Main Endeavour Field (MEF) on the Juan de Fuca Ridge, off the coast of Washington State and Vancouver Island, BC, between July 2017 – May 2019 and April 2019 – August 2019. Using Ocean Network Canada (ONC) data and a University of Washington (UW) compiled earthquake catalogue, the earthquake frequency, magnitude, and moment were compared to fluctuating temperature and resistivity at MEF. It seems temperature and resistivity are affected by seismic activity; however, other factors may need to be taken into consideration. After major earthquake events, temperature steadily increases over a span of a few months and resistivity fluctuates to max and min values rapidly. Understanding how temperature and resistivity responds to seismic activity will help determine secondary effects on properties such as salinity, volatile species, and any organisms living near these vents.