A seismic pressure and acceleration sensor (322; 422; 522; 622), comprising: an enclosure (346; 446; 546; 646) having a pair of opposing parallel walls (327; 427; 527; 627) and a support structure, wherein the pair of opposing parallel walls is less rigid than the support structure; characterized by: a flexible substrate (344; 444; 544; 644) spanning an interior of the enclosure and mechanically coupled to the support structure of the enclosure, the flexible substrate parallel to the pair of opposing parallel walls; wherein the pair of opposing parallel walls and the flexible substrate are mechanically isolated from one another; a first piezoelectric structure (342-1; 442-1; 542-1; 642-1) for measuring the pressure and that is coupled to a first wall (327-1; 427-1; 527-1; 627-1) of the pair of opposing parallel walls; a second piezoelectric structure (342-2; 442-2; 542-2; 642-2) for measuring the pressure and that is coupled to a second wall (327-2; 427-2; 527-2; 627-2) of the pair of opposing parallel walls; a third piezoelectric structure for measuring the acceleration and that is (325; 425; 525; 625) coupled to the flexible substrate: a first electrical connection (350-1; 450-1; 550-1; 650-1) to the first piezoelectric structure; a second electrical connection (350-2; 450-2; 550-2; 650-2) to the first piezoelectric structure; a third electrical connection (348-1; 448-1; 548-1; 648-1) to the second piezoelectric structure; and a fourth electrical connection (348-2; 448-2; 548-2; 648-2) to the second piezoelectric structure. an enclosure (346; 446; 546; 646) having a pair of opposing parallel walls (327; 427; 527; 627) and a support structure, wherein the pair of opposing parallel walls is less rigid than the support structure; characterized by: a flexible substrate (344; 444; 544; 644) spanning an interior of the enclosure and mechanically coupled to the support structure of the enclosure, the flexible substrate parallel to the pair of opposing parallel walls; wherein the pair of opposing parallel walls and the flexible substrate are mechanically isolated from one another; a first piezoelectric structure (342-1; 442-1; 542-1; 642-1) for measuring the pressure and that is coupled to a first wall (327-1; 427-1; 527-1; 627-1) of the pair of opposing parallel walls; a second piezoelectric structure (342-2; 442-2; 542-2; 642-2) for measuring the pressure and that is coupled to a second wall (327-2; 427-2; 527-2; 627-2) of the pair of opposing parallel walls; a third piezoelectric structure for measuring the acceleration and that is (325; 425; 525; 625) coupled to the flexible substrate: a first electrical connection (350-1; 450-1; 550-1; 650-1) to the first piezoelectric structure; a second electrical connection (350-2; 450-2; 550-2; 650-2) to the first piezoelectric structure; a third electrical connection (348-1; 448-1; 548-1; 648-1) to the second piezoelectric structure; and a fourth electrical connection (348-2; 448-2; 548-2; 648-2) to the second piezoelectric structure. a flexible substrate (344; 444; 544; 644) spanning an interior of the enclosure and mechanically coupled to the support structure of the enclosure, the flexible substrate parallel to the pair of opposing parallel walls; wherein the pair of opposing parallel walls and the flexible substrate are mechanically isolated from one another; a first piezoelectric structure (342-1; 442-1; 542-1; 642-1) for measuring the pressure and that is coupled to a first wall (327-1; 427-1; 527-1; 627-1) of the pair of opposing parallel walls; a second piezoelectric structure (342-2; 442-2; 542-2; 642-2) for measuring the pressure and that is coupled to a second wall (327-2; 427-2; 527-2; 627-2) of the pair of opposing parallel walls; a third piezoelectric structure for measuring the acceleration and that is (325; 425; 525; 625) coupled to the flexible substrate: a first electrical connection (350-1; 450-1; 550-1; 650-1) to the first piezoelectric structure; a second electrical connection (350-2; 450-2; 550-2; 650-2) to the first piezoelectric structure; a third electrical connection (348-1; 448-1; 548-1; 648-1) to the second piezoelectric structure; and a fourth electrical connection (348-2; 448-2; 548-2; 648-2) to the second piezoelectric structure. a first electrical connection (350-1; 450-1; 550-1; 650-1) to the first piezoelectric structure; a second electrical connection (350-2; 450-2; 550-2; 650-2) to the first piezoelectric structure; a third electrical connection (348-1; 448-1; 548-1; 648-1) to the second piezoelectric structure; and a fourth electrical connection (348-2; 448-2; 548-2; 648-2) to the second piezoelectric structure.