Abstract: A mass positioning apparatus for use with seismic sensors is described. The seismic sensor includes axis mechanics including a pivotable boom with a defined null point. The mass positioning apparatus comprising: adjustment means for positioning the boom at the null point; actuator means for moving the adjustment means; and means for determining a position of the adjustment means relative to an operational range of travel.

Abstract: A seismometer comprising a pressure sealed enclosure; an electrical component; an axis mechanics assembly having moving components, the axis mechanics assembly being in electrical communication with the electrical component; and a thermally insulating assembly mechanically supporting and surrounding the axis mechanics assembly for minimizing heat flow from the pressure sealed enclosure to the axis mechanics assembly and for enabling transmission of a seismic signal to the axis mechanics assembly, wherein the pressure sealed enclosure encloses the axis mechanics assembly, the thermally insulating assembly, and the electrical component.