The book that Danny is resting his head on is "Karate-Do: My Way of Life" by Gichin Funakoshi, one of the great masters of Karate who helped to introduce the martial art to Japan at the First National Athletic Exhibition in Tokyo in 1922.
A 10-66 is the NYPD radio code for a unusual incident such as a train derailment, plane crash, building collapse or in this case an earthquake.
The rare katana that Danny and Colleen find is called a Tsukamoto which is a reference to Japanese film director Shin'ya Tsukamoto who directed Tetsuo: The Iron Man (1989).