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Solomon Islands (archipelago)

Archipelago in the South Pacific Ocean spread over two countries

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Solomon Islands map, modified and cropped from PCL map collection Courtesy of the University of Texas Libraries, The University of Texas at Austin. According to the University of Texas , " most of the
U.S. Central Intelligence Agency · Public domain

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Through Archipelago, Coral and Volcano

Geography

The Solomon Islands archipelago consists of over 1,000 islands, ranging from low-lying coral atolls to mountainous volcanic islands, including many volcanoes with varying degrees of activity. Bougainville Island is the largest in the archipelago, with an area of 9,300 square kilometres (3,600 sq mi). Mount Balbi on Bougainville is the highest peak in the archipelago at 2,715 metres (8,907 ft).

Geology

The Solomon Islands archipelago was formed by the convergence of the Indo-Australian Plate and the Pacific Plate. The Indo-Australian Plate and the smaller Solomon Sea Plate are subducting beneath the Pacific Plate along the New Britain–San Cristobal oceanic trench, which runs south of and parallel to the archipelago in the Solomon Sea. The surface geology of the islands is mostly igneous rocks, outcrops of metamorphic rocks, alluvial lowlands, and uplifted coral islands. Areas of ancient coralline limestone are found on Bougainville.

Active and dormant volcanoes are found in an arc extending from Bougainville in the north through the New Georgia Islands and Savo Island to Gallego volcano on the northwest end of Guadalcanal. Arc volcanism dates the earliest volcanoes on the islands to the Early/Middle Eocene.

The archipelago is bounded both to the northeast and southwest by subduction zones, which pull in opposing directions. The rates of subduction on various zones have varied greatly over time due to the subduction of rough seafloor features, such as seamounts. Several ridges have been subducted, associated with periods of tectonic uplift on certain islands, again with highly variable rates. However, it is believed that subduction around the Solomon Islands represents one of the highest rates of convergence found on Earth at 10–12 cm/yr.

Subduction zones around the archipelago are tectonically active, though recorded seismicity is higher on the southern side of the island chain. The largest recorded earthquake from the Solomon Islands was a Mw 8.1 that occurred on April 1, 2007.

Climate

The climate of the islands is tropical; however, temperatures do not greatly fluctuate due to the heat sink of the surrounding ocean. Daytime temperatures are normally 25 to 32 °C (77 to 90 °F) and 13 to 15 °C (55 to 59 °F) at night. From April to October (the dry season), the southeast trade winds blow, gusting at times up to 30 knots (55 km/h; 35 mph) or more.

November to March is the wet season, caused by the northwest monsoon, and is typically warmer and wetter. Cyclones arise in the Coral Sea and the area of the Solomon Islands, but they usually veer toward New Caledonia and Vanuatu or down the coast of Australia.

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