Suruga Bay

Suruga Bay is a large body of water on the Pacific coast of Honshū, Japan. It is located within the Shizuoka Prefecture. The bay is positioned north of a straight line between Omaezaki Point and Irōzaki Point. This point sits at the tip of the Izu Peninsula. The land of Honshū surrounds the bay to the west and the southwest. The Izu Peninsula forms the eastern boundary of the water.

The physical shape of the bay changes depending on where you stand. The western and central coastlines are quite different from the east. From Shizuoka to Numazu, the coast features sandy beaches. You can find these at places like Yuigahama and Tagonoura. However, the eastern and northeastern stretches are much different. From Numazu down the southwestern coast of the Izu Peninsula, the land is rocky. The eastern end also contains several small rocky islands. Some of these islands are joined to the mainland by tombolos. A tombolo is a ridge of sand that connects an island to the shore.

Geology explains the extreme depth and movement of the bay. The bay was formed by tectonic subduction. This happens when the Philippine Sea Plate moves under the Eurasian Plate. This process occurs at the Suruga Trough. The Suruga Trough runs through the middle of the bay. It is the deepest trough in all of Japan. This subduction also makes the area a source of considerable seismic activity. This means the region experiences many earthquakes due to the moving plates.

Water flows into the bay from many different directions. Numerous rivers empty into the western portion of the bay. These include the Fuji, Ōi, and Abe rivers. As these rivers flow into the sea, they carve out submarine canyons. These are deep valleys on the ocean floor. At the easternmost end, the Kano River flows into a pocket called Uchiura-wan. This pocket is located at Numazu, Shizuoka.

The bay is a very active place for both nature and people. It is open to the Philippine Sea and the Pacific Ocean to the south. The Izu Peninsula acts as a shield against large oceanic waves. This protection creates conditions that are good for many activities. People use the bay for fishing, sailing, windsurfing, and swimming. Scientists also use the area to study deep-sea organisms. One specific area is very important for the fishing industry. This is an undersea plateau called Senoumi at the southwest end. It is well known as a rich fishing ground.

Suruga Bay has also faced significant environmental challenges. Since the post-war industrial boom in Japan, the bay has suffered from severe pollution. By 1970, the situation in Fuji was very serious. Local paper mills produced massive amounts of wastewater every day. This amount was equivalent to the daily sewage produced by Tokyo at that time. The waste created a thick, sulphur-laden sludge. This sludge was so thick it threatened to block the harbor. To fix this, workers had to perform dredging. However, this process severely damaged the local marine life.

Local citizens and fishermen fought to protect their waters. They held protests to pressure the government to take action. This led to new regulations for industry. Even with these rules, pollution remains a concern for scientists. Surveys in the mid-2010s showed intense contamination. They found chemicals known as PCB and PBDE in the sea life. This history of pollution became part of popular culture. The 1971 film Godzilla vs. Hedorah featured the bay. The monster's name comes from the Japanese word "hedoro," which means mud. In the movie, the creature feeds on the heavy pollution in the bay.