It is also Ms. Mizota's job to drop the streamer cable into the ocean. The cable is 6,000m long and contains 444 receivers.
Multi-Channel Seismic Reflection Survey (MCS) and a seismic refraction survey using ocean-bottom seismographs
Pressurized air is emitted from the airgun, which is towed by the research vessel, causing an artificial seismic wave. The streamer cable and the ocean-bottom seismographs catch the seismic wave. The structure beneath the ocean floor is surveyed through the relative strength of the reflected wave, which is similar in mechanism to CT scans scanning the human body. The streamer cable reeled out on to the ocean extends to approximately 6,000m. The research vessel tows the cable and sails for 500km, maintaining a set speed.

The necessity for earthquake research was what determined 6K's maximum depth of 6,500m. Investigation and research to prepare for massive earthquakes remain one of JAMSTEC's highest priority research themes.
JAMSTEC is currently working on the Dense Oceanfloor Network System for Earthquakes and Tsunamis, which is the first of its kind in the world, in Kumanonada off of the Kii Peninsula, the assumed epicenter of the Tonankai Earthquake. The project is a submarine cabled system with strategically-placed, high-precision seismographs and tsunami recorders that monitor vital information in real time and aim for the early detection of earthquakes and tsunamis. The data acquired from this network is hoped to become useful in understanding the mechanism of earthquakes and predict their occurrence.
JAMSTEC, for the past ten years, has also been continuously investigating the structures under the seabed using the Multi-Channel-Seismic Survey System (MCS). Seismic waves are artificially produced through a sound source, known as the airgun, and by receiving the seismic reflection from the seabed boundary on the streamer-cable and analyzing the acquired data, a detailed picture of the crustal structure a dozen kilometers below the seafloor may be obtained. This survey has produced a number of invaluable results, including the discovery of a spray fault thought to have caused massive ocean-trench earthquakes in the past.
Ayumi Mizota joined Nippon Marine Enterprises, Ltd. in 2004 and as the leader of the MCS analysis team rides and conducts research on the deep-sea research vessel Kairei, which is operated by the Nippon Marine Enterprises, Ltd. Creating cross-sectional diagrams based on the enormous volumes of data transmitted from the streamer cable requires an inordinate amount of patience. Since the data could contain "noise" (errors) caused by passing ships, picking out the true data from the false becomes essential. However, "knowing that these low-key but steady efforts will lead to elucidating the mechanism of earthquake occurrence make them even more rewarding."
Ms. Mizota also participated in the emergency research following the 2004 Sumatra earthquake and was able to see first hand the massive rifts and caving in of the seafloor. Ms. Mizota believes that part of the appeal of her job is that by working on such projects as the MCS research of the Izu/Ogasawara area as part of the government's Continental Shelf Survey and the exploration of the crustal structure off Kashiwazaki in connection with the 2007 Niigataken Chuetsu-oki Earthquake, she is able to engage in timely and high-profile surveys that are socially significant.
It should be noted that in the film, Japan Sinks, the heroine was a member of the hyper-rescue squad of the Tokyo Fire Department, traditionally a bastion of male dominance. Ms. Mizota has also immersed herself in a traditionally male-dominated world.
"Actually, that is not the case. I was never really conscious of the fact that I was a female. And it hasn't been a handicap in my line of work. People do not treat me any differently. In the past, I have been told that the ships did not have ladies' rooms, but now they are fully equipped. I believe there will be more and more women joining this line of work."