Seismic sensor devices

A seismic sensor installation comprising a sensor device installed at a land-air boundary, wherein the sensor device comprises:

• a fluid-filled housing;
• and
• a sensor arrangement supported within the housing and coupled directly to the fluid as to detect movement thereof.

A seismic sensor installation comprising plural sensor devices installed at a land-air boundary, wherein the installation comprises plural sensor devices absent of hydrophones and, adjacent an obstacle, plural sensor devices comprising:

• a fluid-filled housing;
• and
• a hydrophone and one or more geophones or accelerometers supported within the housing and coupled directly to the fluid as to detect movement thereof.

A method for sensing compressional waves at a land-air boundary, comprising:

• positioning a fluid-based sensor system proximal to the land-air boundary, wherein he fluid-based sensor system comprises a housing, a fluid disposed within the housing and one or more sensors coupled directly to the fluid;
• and
• using the one or more sensor to detect movement of the fluid.