As the crust on and under the seafloor reacts with seawater, many of the minerals get altered from those without structural H2O to those with it. The most common of the latter minerals involved in seafloor alteration is serpentine. When this mineral forms, there is a large increase in the volume of the rock (up to a 40%). Due to the complex interplay of a variety of parameters such as temperature and temperature gradients, composition, water-rock ratio, mineral reaction, confining pressure, faulting, etc. our understanding of the impact of serpentinization on crack propagation in ocean crust, faulting, and other types of deformation both small and large, is limited. This research addresses this issue through an integrated approach that involves developing and applying theories for crack initiation and propagation in seafloor rocks and using the results to understand the formation of tectonic and structural features we see on and below the seafloor, features that tend to be associated with hydrothermal vent systems and seafloor faulting and deformation. Research will be carried out using mathematical models that have been revised to incorporate additional essential parameters and more precise equations to simulate crack initiation and propagation. Models will be modified to allow calculation of stresses and strains to determine the importance of large scale faulting and fracturing on internal and external serpentinized bodies. Results of the modeling will be checked against observational data from the Atlantis Massif, part of the Mid-Atlantic Ridge system and the Hyuganada Forearc region southwest of Japan. Broader impacts of the project include building infrastructure for science by producing models and modeling codes that have the potential to crossover into the fields of ore deposit and energy research. It also helps improve our ability to tap the potential of using mafic and ultramafic rocks on and below the seafloor as possible carbon sequestration sites for atmospheric carbon. Training of students, of which one is from a gender under-represented in the sciences, in computational geoscience is also involved, as is integration of research results into classroom training for undergraduate students.