Mid ocean ridges are sites of creation of new ocean floor, a process that is characterized by high seismicity (earthquakes) and active volcanism, and vigorous hydrothermal circulation. The latter is evidenced by jets of super heated water rising from vents in the sea floor (the now-famous black smokers) that support exotic biological communities. An important scientific goal is understanding the dynamics of these systems. Earthquakes occur within the upper brittle crust in response to stresses and their distribution in space and time is a primary source of information about dynamic subsurface geologic processes. These earthquakes are associated with both the tectonic and magmatic events that account for plate spreading and they create fractures that influence the patterns of hydrothermal circulation, heat extraction and water-rock reactions. As such, long duration studies of micro-earthquakes are key to multidisciplinary studies of the dynamic processes are mid-ocean ridges. The objectives of this project are to infer spatial and temporal patterns of stress changes associated with the earthquake swarms in late January and February 2005, to understand the impact of the associated regional spreading event on the characteristics of hydrothermal systems and magmatic segmentation, and to determine how stress changes associated with the regional spreading event affect seismic anisotropy and tidal triggering.
