A seismic pressure and acceleration system, comprising: a marine streamer (120; 520); and a plurality of sensors (322; 422; 522) positioned within the marine streamer, characterized in that at least one of the plurality of sensors comprises: a hydrophone comprising: a volume encapsulated by an air-tight enclosure (346; 446; 546) composed of electrically conductive material, the enclosure comprising: opposing parallel walls (327; 427; 527) having pressure-sensitive surfaces separated by a pressure-insensitive support structure more rigid than the opposing parallel walls (327; 427; 527), wherein a first wall (327-1; 427-1; 527-1) of the opposing parallel walls is coupled to a first piezoelectric structure (342-1; 442-1; 542-1) and a second wall (327-2; 427-2; 527-2) of the opposing parallel walls is coupled to a second piezoelectric structure (342-2; 442-2; 542- 2); and an accelerometer positioned within the encapsulated volume, wherein: the accelerometer is mechanically isolated from the pressure-sensitive surface; the accelerometer is mechanically coupled to the support structure; and the accelerometer comprises: a flexible substrate (344; 444; 544) spanning an interior of the enclosure (346; 446; 546) and mechanically coupled to the support structure, the flexible substrate parallel to the opposing parallel walls (327; 427; 527); and a third piezoelectric structure (325; 425; 525) coupled to the flexible substrate (344; 444; 544). a marine streamer (120; 520); and a plurality of sensors (322; 422; 522) positioned within the marine streamer, characterized in that at least one of the plurality of sensors comprises: a hydrophone comprising: a volume encapsulated by an air-tight enclosure (346; 446; 546) composed of electrically conductive material, the enclosure comprising: opposing parallel walls (327; 427; 527) having pressure-sensitive surfaces separated by a pressure-insensitive support structure more rigid than the opposing parallel walls (327; 427; 527), wherein a first wall (327-1; 427-1; 527-1) of the opposing parallel walls is coupled to a first piezoelectric structure (342-1; 442-1; 542-1) and a second wall (327-2; 427-2; 527-2) of the opposing parallel walls is coupled to a second piezoelectric structure (342-2; 442-2; 542- 2); and an accelerometer positioned within the encapsulated volume, wherein: the accelerometer is mechanically isolated from the pressure-sensitive surface; the accelerometer is mechanically coupled to the support structure; and the accelerometer comprises: a flexible substrate (344; 444; 544) spanning an interior of the enclosure (346; 446; 546) and mechanically coupled to the support structure, the flexible substrate parallel to the opposing parallel walls (327; 427; 527); and a third piezoelectric structure (325; 425; 525) coupled to the flexible substrate (344; 444; 544). a hydrophone comprising: a volume encapsulated by an air-tight enclosure (346; 446; 546) composed of electrically conductive material, the enclosure comprising: opposing parallel walls (327; 427; 527) having pressure-sensitive surfaces separated by a pressure-insensitive support structure more rigid than the opposing parallel walls (327; 427; 527), wherein a first wall (327-1; 427-1; 527-1) of the opposing parallel walls is coupled to a first piezoelectric structure (342-1; 442-1; 542-1) and a second wall (327-2; 427-2; 527-2) of the opposing parallel walls is coupled to a second piezoelectric structure (342-2; 442-2; 542- 2); and a volume encapsulated by an air-tight enclosure (346; 446; 546) composed of electrically conductive material, the enclosure comprising: opposing parallel walls (327; 427; 527) having pressure-sensitive surfaces separated by a pressure-insensitive support structure more rigid than the opposing parallel walls (327; 427; 527), wherein a first wall (327-1; 427-1; 527-1) of the opposing parallel walls is coupled to a first piezoelectric structure (342-1; 442-1; 542-1) and a second wall (327-2; 427-2; 527-2) of the opposing parallel walls is coupled to a second piezoelectric structure (342-2; 442-2; 542- 2); and an accelerometer positioned within the encapsulated volume, wherein: the accelerometer is mechanically isolated from the pressure-sensitive surface; the accelerometer is mechanically coupled to the support structure; and the accelerometer comprises: a flexible substrate (344; 444; 544) spanning an interior of the enclosure (346; 446; 546) and mechanically coupled to the support structure, the flexible substrate parallel to the opposing parallel walls (327; 427; 527); and a third piezoelectric structure (325; 425; 525) coupled to the flexible substrate (344; 444; 544). the accelerometer is mechanically isolated from the pressure-sensitive surface; the accelerometer is mechanically coupled to the support structure; and the accelerometer comprises: a flexible substrate (344; 444; 544) spanning an interior of the enclosure (346; 446; 546) and mechanically coupled to the support structure, the flexible substrate parallel to the opposing parallel walls (327; 427; 527); and a third piezoelectric structure (325; 425; 525) coupled to the flexible substrate (344; 444; 544).