Scripps Institution of Oceanography will undertake a collaborative instrument development project to develop, construct, and test a low-cost, three-axis tiltmeter which can be easily deployed for long durations of up to two years on the seafloor to measure crustal deformation. The new sensors will employ precision optical detection technology to measure the deflection of a small pendulum with a precision of 1 microradian and very small drift. The entire unit including data logger will be housed in a pressure case. An array of these new tilt sensors would be needed for scientific experiments along mid-ocean ridges where volcanic activity deforms the crust of the seafloor and hence tilts the sensors. The amount and direction of tilt then provides information on subsurface volcanic activity. Such information has been deemed important for planned long-term seafloor observatories associated with the RIDGE global change research program.