The Galapagos Islands belong to Ecuador, in South America. The official name is the Colon Archipelago. It consists of many volcanic islands located about 1,000 kilometers west of the continent, lying nearly on the equator in the Eastern Pacific. The islands were created on a hotspot from which magma burst through the Nazca plate, and are scattered in the ocean between the east longitudes of 89 degrees 16 minutes and 92 degrees 01 minute, and between 1 degree 36 minutes north and 1 degree 40 minutes south (about 260 kilometers from east to west and 200 kilometers from north to south).

The Nazca plate moves five centimeters a year toward the east south east, leaving older islands, such as the 5-6 million-year-old San Cristobal at the eastern end and Espanola at the southeastern end, and creating younger islands, such as 60-300 thousand years old Fernandina and Isabela in the west. The younger islands often erupt, even today. The highest mountain is Wolf Volcano in Isabela, 1,707 meters above sea level.

Ocean current

The Galapagos Islands are influenced by three ocean currents. The cold South Equatorial Current flows westward into Galapagos waters, which comes from the Peruvian Current (the Humboldt Current) that runs north along the continent of South America and turns west near the equator. The warm Panama Current runs in from north. In addition, the deep sea Cromwell Current runs from the west and is a source of upwelling when it hits the islands to bring nutrients from the bottom up to the surface layer.

Weather and climate

The Galapagos Islands lie in the southeastern trade wind zone in the equatorial eastern Pacific. When the trade wind weakens between January and April, the South Equatorial Current flows on the south side. The Galapagos then warm up and the warm season (rainy season) arrives. In June, the trade wind strengthens and the cold South Equatorial Current flows around the whole archipelago. The air temperature then drops marking the arrival of the garua season (misty, cloudy season), when no rain falls in the lowland, and cloud and mist envelop the highland. Thus, The Galapagos have two seasons. In the south shore of Santa Cruz Island, lying nearly at the center of the archipelago, the annual precipitation is 512 mm; the average air temperature is 29.1 degrees Celsius in March, the warmest month, and 23.1 degrees Celsius in September, the coldest month. The annual average air temperature there is 25.4 degrees Celsius. The cold South Equatorial Current maintains an arid subtropical climate in the Galapagos, which lie in the equatorial zone.

An irregular phenomenon called El Nino occurs once in 5-6 years. The water temperature rises, which raises air temperature and bring plentiful precipitation along the continental coast of South America and the equator. The Galapagos lie right in the middle of El Nino. During the El Nino in 1982-83, the maximum sea level, the maximum temperature of the surface water, and the maximum air temperature rose 40 cm, 4 degrees Celsius, and 3 degrees Celsius, respectively, over those values in ordinary years. Also the average monthly precipitation and the annual precipitation increased 10-fold and eightfold, respectively. By contrast, the sea level, and the air temperature, and precipitation decreases in years when the phenomenon called La Nina occurs.