Tides of Fire by James Rollins Sigma Force #17

Sigma Force is back with one of its wildest missions ever.  Earthquakes and erupting volcanoes are causing havoc across the Southeast China seas, and nothing about this is natural. While Chinese warships search for a sunken nuclear submarine, Gray and company must find clues to a similar event that happened during the eighteen hundreds.

Rollins gives another rollercoaster ride, this time six miles beneath the ocean where the unbelievable is happening. As always, fact and fiction become blurred in this high-stakes thriller.