Compliance Chambers for Marine Vibrators

A method comprising:

• disposing a marine vibrator in a body of water in conjunction with a geophysical survey, wherein the marine vibrator comprises:
• a containment housing, where the containment housing defines at least a portion of a marine vibrator internal volume having a marine vibrator internal gas pressure;
• a sound radiating surface;
• and
• a compliance chamber, wherein the compliance chamber comprises:
• a compliance chamber housing, wherein the compliance chamber housing defines at least a portion of a compliance chamber internal volume having a chamber gas spring;
• a non-linear linkage assembly;
• and
• a low pressure chamber, wherein the low pressure chamber comprises:
• a low pressure piston coupled to the non-linear linkage assembly, and
• a low pressure chamber housing, wherein the low pressure chamber housing defines at least a portion of a low pressure chamber internal volume having a low pressure chamber internal gas pressure;
• triggering the marine vibrator to cause the sound radiating surface in the marine vibrator to move back and forth, the triggering resulting in a displacement of a portion of the marine vibrator internal volume;
• and
• moving the low pressure piston in response to the displacement of the portion of the marine vibrator internal volume to adjust a resonance frequency of the marine vibrator.

A method comprising:

• disposing a marine vibrator comprising a marine vibrator internal gas pressure and a low pressure piston in a body of water at a first depth, wherein the marine vibrator has a first resonance frequency at the first depth;
• subsequently disposing the marine vibrator in the body of water at a second depth, wherein the second depth is greater than the first depth, and wherein the marine vibrator has a second resonance frequency at the second depth;
• and
• allowing marine vibrator internal gas pressure to act on the low pressure piston such that the first resonance frequency differs from the second resonance frequency by no more than 25%.