Clive Cussler's The devil's sea / Dirk Cussler.

Tibet, 1959. In the turmoil of the Communist takeover of the mountain kingdom, a Buddhist artefact of immense importance appears to have been lost to history. Until, sixty years later, clues to its survival emerged from the wreckage of a cargo plane discovered deep beneath the surface of the Philippine Sea . . . NUMA Director Dirk Pitt and his old friend Al Giordino already have their hands full dealing with the recovery of a top secret hypersonic missile that went down in the Luzon Strait. Especially when it becomes clear that a rogue Chinese military team has its sights set on the same prize. And that, after making their own earth-shattering discovery about what lies below the waves, they're prepared to go to any lengths to ensure that they possess it. Any lengths at all.