A pressure-balanced seismic sensor package , comprising: a plurality of optical components , wherein the plurality of optical components comprises an optical accelerometer ; a sensor box with an interior to enclose the plurality of optical components and comprising: a first compartment housing the optical accelerometer of the plurality of optical components ; and a second compartment separated from the first compartment by a dividing wall , and housing a second optical component of the plurality of optical components ; the pressure-balanced seismic sensor package being characterized in that it further comprises a lid for the sensor box , comprising: a first flexible component (428-1, 928-1) formed in a first portion (410-1) of the lid over the first compartment ; and a second flexible component (428-2, 928-2) formed in a second portion (410-2) of the lid over the second compartment , wherein the first (428-1, 928-1) and the second (428-2, 928-2) flexible components are formed to contribute to a pressure-balance of the sensor box by an alteration of shape of the first (428-1, 928-1) and the second (428-2, 928-2) flexible components in response to a change in an external pressure. a plurality of optical components , wherein the plurality of optical components comprises an optical accelerometer ; a sensor box with an interior to enclose the plurality of optical components and comprising: a first compartment housing the optical accelerometer of the plurality of optical components ; and a second compartment separated from the first compartment by a dividing wall , and housing a second optical component of the plurality of optical components ; the pressure-balanced seismic sensor package being characterized in that it further comprises a lid for the sensor box , comprising: a first flexible component (428-1, 928-1) formed in a first portion (410-1) of the lid over the first compartment ; and a second flexible component (428-2, 928-2) formed in a second portion (410-2) of the lid over the second compartment , wherein the first (428-1, 928-1) and the second (428-2, 928-2) flexible components are formed to contribute to a pressure-balance of the sensor box by an alteration of shape of the first (428-1, 928-1) and the second (428-2, 928-2) flexible components in response to a change in an external pressure. a first compartment housing the optical accelerometer of the plurality of optical components ; and a second compartment separated from the first compartment by a dividing wall , and housing a second optical component of the plurality of optical components ; the pressure-balanced seismic sensor package being characterized in that it further comprises a lid for the sensor box , comprising: a first flexible component (428-1, 928-1) formed in a first portion (410-1) of the lid over the first compartment ; and a second flexible component (428-2, 928-2) formed in a second portion (410-2) of the lid over the second compartment , wherein the first (428-1, 928-1) and the second (428-2, 928-2) flexible components are formed to contribute to a pressure-balance of the sensor box by an alteration of shape of the first (428-1, 928-1) and the second (428-2, 928-2) flexible components in response to a change in an external pressure. a first flexible component (428-1, 928-1) formed in a first portion (410-1) of the lid over the first compartment ; and a second flexible component (428-2, 928-2) formed in a second portion (410-2) of the lid over the second compartment , wherein the first (428-1, 928-1) and the second (428-2, 928-2) flexible components are formed to contribute to a pressure-balance of the sensor box by an alteration of shape of the first (428-1, 928-1) and the second (428-2, 928-2) flexible components in response to a change in an external pressure. <EOS>