Seismic data acquisition with extended dynamic range

Marine seismic data acquisition apparatus, comprising:

• a sensor having an electrical sensor output and configured to sense seismic energy in a body of water;
• a first data acquisition subchannel configured to exhibit a first gain and comprising a first subchannel input, a first input protection circuit, an impedance isolator, and an internal input protection circuit, wherein the first subchannel input is coupled to the sensor output, the first input protection circuit is coupled between the first subchannel input and an input of the impedance isolator, and the internal input protection circuit is coupled to an output of the impedance isolator;
• and
• a second data acquisition subchannel configured to exhibit a second gain lower than the first gain and comprising a second subchannel input and a second input protection circuit, wherein the second subchannel input is coupled to the sensor output and to the second input protection circuit;
• wherein the sensor output and the first and second input protection circuits are configured such that neither the first input protection circuit nor the second input protection circuit will activate when seismic energy reaching the sensor has a peak amplitude less than a first threshold level;
• wherein the internal input protection circuit is configured to activate when seismic energy reaching the sensor has a peak amplitude greater than a second threshold level;
• and
• wherein the second threshold level is lower than the first threshold level.