Mariana Islands in the context of "Captaincy General of the Philippines"

The Philippine Sea is a marginal sea of the Western Pacific Ocean east of the Philippine Archipelago and the largest sea in the world, occupying an estimated surface area of 5 million square kilometers (2×10^ sq mi). The Philippine Sea Plate forms the floor of the sea. Its western border is the first island chain to the west, comprising the Ryukyu Islands in the northwest and Taiwan in the west. Its southwestern border comprises the Philippine islands of Luzon, Catanduanes, Samar, Leyte, and Mindanao. Its northern border comprises the Japanese islands of Honshu, Shikoku and Kyūshū. Its eastern border is the second island chain to the east, comprising the Bonin Islands and Iwo Jima in the northeast, the Mariana Islands (including Guam, Saipan, and Tinian) in the due east, and Halmahera, Palau, Yap and Ulithi (of the Caroline Islands) in the southeast. Its southern border is Indonesia's Morotai Island.

The sea has a complex and diverse undersea relief. The floor is formed into a structural basin by a series of geologic faults and fracture zones. Island arcs, which are actually extended ridges protruding above the ocean surface due to plate tectonic activity in the area, enclose the Philippine Sea to the north, east and south. The Philippine archipelago, Ryukyu Islands, and the Marianas are examples. Another prominent feature of the Philippine Sea is the presence of deep sea trenches, among them the Philippine Trench and the Mariana Trench, containing the deepest point on the planet.

The Izu–Bonin–Mariana (IBM) arc system is a tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Islands, and the Mariana Islands; much more of the IBM arc system is submerged below sealevel. The IBM arc system lies along the eastern margin of the Philippine Sea plate in the Western Pacific Ocean. It is the site of the deepest gash in Earth's solid surface, the Challenger Deep in the Mariana Trench.

The IBM arc system formed as a result of subduction of the western Pacific plate. The IBM arc system now subducts mid-Jurassic to Early Cretaceous lithosphere, with younger lithosphere in the north and older lithosphere in the south, including the oldest (~170 million years old, or Ma) oceanic crust. Subduction rates vary from ~2 cm (1 inch) per year in the south to 6 cm (~2.5 inches) in the north.

The Nanpō Islands (南方諸島, Nanpō Shotō) is a collective term for the groups of islands that are located to the south of the Japanese archipelago. They extend from the Izu Peninsula west of Tokyo Bay southward for about 1,200 km (750 mi), to within 500 km (310 mi) of the Mariana Islands. The Nanpō Islands are all administered by Tokyo Metropolis.

The Hydrographic and Oceanographic Department of the Japan Coast Guard defines the Nanpō Shotō as follows:

The Treaty of Peace between the United States of America and the Kingdom of Spain, commonly known as the Treaty of Paris of 1898, was signed by Spain and the United States on December 10, 1898, and marked the official end of the Spanish–American War. Under it, Spain relinquished all claim of sovereignty over the West Indies archipelagos and islands of Cuba and Puerto Rico in the Caribbean, the Western Pacific island of Guam in the Marianas archipelago in Micronesia, and the Western Pacific archipelago of the Philippines in Southeast Asia to the United States. The cession of the Philippines involved a compensation of $20 million from the United States to Spain.

The treaty was preceded by the Spanish-American War armistice, a preliminary peace agreement signed on August 12, 1898 in Washington, DC. The armistice formally stopped the active hostilities between Spain and the United States, requiring Spain to cede Cuba, Puerto Rico, and Guam to the United States, and to agree to the American occupation of Manila in the Philippines. The treaty came into effect on April 11, 1899, when the documents of ratification were exchanged. It was the first treaty negotiated between the two governments since the 1819 Adams–Onís Treaty.

Micronesia (UK: /ˌmaɪkrəˈniːziə/, US: /-ˈniːʒə/ ) is a subregion of Oceania, consisting of approximately 2,000 small islands in the Northwestern Pacific Ocean. It has a close shared cultural history with three other island regions: Maritime Southeast Asia to the west, Polynesia to the east, and Melanesia to the south—as well as with the wider community of Austronesian peoples.

The region has a tropical marine climate and is part of the Oceanian realm. It includes four main archipelagos—the Caroline Islands, the Gilbert Islands, the Mariana Islands, and the Marshall Islands — as well as numerous islands that are not part of any archipelago.

On 6 and 9 August 1945, the United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki, respectively, during World War II. The aerial bombings killed 150,000 to 246,000 people, most of whom were civilians, and remain the only uses of nuclear weapons in an armed conflict. Japan announced its surrender to the Allies on 15 August, six days after the bombing of Nagasaki and the Soviet Union's declaration of war against Japan and invasion of Manchuria. The Japanese government signed an instrument of surrender on 2 September, ending the war.

In the final year of World War II, the Allies prepared for a costly invasion of the Japanese mainland. This undertaking was preceded by a conventional bombing and firebombing campaign that devastated 64 Japanese cities, including an operation on Tokyo. The war in Europe concluded when Germany surrendered on 8 May 1945, and the Allies turned their full attention to the Pacific War. By July 1945, the Allies' Manhattan Project had produced two types of atomic bombs: "Little Boy", an enriched uranium gun-type fission weapon, and "Fat Man", a plutonium implosion-type nuclear weapon. The 509th Composite Group of the U.S. Army Air Forces was trained and equipped with the specialized Silverplate version of the Boeing B-29 Superfortress, and deployed to Tinian in the Mariana Islands. The Allies called for the unconditional surrender of the Imperial Japanese Armed Forces in the Potsdam Declaration on 26 July 1945, the alternative being "prompt and utter destruction". The Japanese government ignored the ultimatum.

Guam (/ˈɡwɑːm/ GWAHM; Chamorro: Guåhan [ˈɡʷɑhɑn]) is an island that is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, and the most populous village is Dededo. It is the westernmost point and territory of the United States, as measured from the geographic center of the U.S. In Oceania, Guam is the largest and southernmost of the Mariana Islands and the largest island in Micronesia. In 2022, its population was 168,801. Chamorros are its largest ethnic group, but a minority on the multiethnic island. The territory spans 210 square miles (540 km; 130,000 acres) and has a population density of 775 per square mile (299/km).

Indigenous Guamanians are the Chamorro, who are related to the Austronesian peoples of the Malay Archipelago, the Philippines, Taiwan, and Polynesia. Unlike most of its neighbors, the Chamorro language is not classified as a Micronesian or Polynesian language. Like Palauan, it possibly constitutes an independent branch of the Malayo-Polynesian language family. The Chamorro people settled Guam and the Mariana islands approximately 3,500 years ago. Portuguese explorer Ferdinand Magellan, while in the service of Spain, was the first European to visit and claim the island in March 1521. Guam was fully colonized by Spain in 1668. Between the 17th and 19th centuries, Guam was an important stopover for Spanish Manila galleons. During the Spanish–American War, the United States captured Guam in June 1898. Under the 1898 Treaty of Paris, Spain ceded Guam to the U.S. effective April 11, 1899.

The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI), is an unincorporated territory and commonwealth of the United States consisting of 14 islands in the northwestern Pacific Ocean. The CNMI includes the 14 northernmost islands in the Mariana Archipelago; the southernmost island, Guam, is a separate U.S. territory. The Northern Mariana Islands were listed by the United Nations as a non-self-governing territory until 1990.

During the colonial period, the Northern Marianas were variously under the control of the Spanish, German, and Japanese empires. After World War II, the islands were part of the United Nations trust territories under American administration before formally joining the United States as a territory in 1986, with their population gaining United States citizenship.

The Philippine Sea plate or the Philippine plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of the Philippine Mobile Belt, which is geologically and tectonically separate from the Philippine Sea plate.

The plate is bordered mostly by convergent boundaries: To the north, the Philippine Sea plate meets the Okhotsk microplate at the Nankai Trough. The Philippine Sea plate, the Amurian plate, and the Okhotsk plate meet near Mount Fuji in Japan. The thickened crust of the Izu–Bonin–Mariana arc colliding with Japan constitutes the Izu Collision Zone. The east of the plate includes the Izu–Ogasawara (Bonin) and the Mariana Islands, forming the Izu–Bonin–Mariana Arc system. There is also a divergent boundary between the Philippine Sea plate and the small Mariana plate which carries the Mariana Islands. To the east, the Pacific plate subducts beneath the Philippine Sea plate at the Izu–Ogasawara Trench. To the south, the Philippine Sea plate is bounded by the Caroline plate and Bird's Head plate. To the west, the Philippine Sea plate subducts under the Philippine Mobile Belt at the Philippine Trench and the East Luzon Trench. (The adjacent rendition of Prof. Peter Bird's map is inaccurate in this respect.) To the northwest, the Philippine Sea plate meets Taiwan and the Nansei islands on the Okinawa plate, and southern Japan on the Amurian plate.It also meets the Yangtze plate due northwest.