Jaggar,Thomas Augustus, Jr.

Jaggar,Thomas Augustus, Jr.,

1871–1953, American geologist and volcanologist, b. Philadelphia, Ph.D. Harvard, 1897. One of the team of U.S. scientists (1902) who surveyed the eruptions in the West Indies of SoufrièreSoufrière
, active volcano, 4,813 ft (1,467 m) high, on Basse-Terre, Guadeloupe, in the Caribbean Sea. Called also La Grande Soufrière, it is the highest mountain in the Lesser Antilles. The volcano erupted in 1976 with no loss of life, as the area had been safely evacuated.
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 and Mt. PeléePelée
, volcano, 4,429 ft (1,350 m) high, on N Martinique, in the West Indies. On May 8, 1902, the day after the eruption of Soufrière on St. Vincent, Pelée also erupted, engulfing Saint-Pierre at its base in a pyroclastic flow and killing c.
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, he became head of the geology department at the Massachusetts Institute of Technology (1906–12). He investigated volcanic and seismic activity in Italy, Central America, Japan, Hawaii, and the Aleutian Islands, and on a trip to Hawaii (1909) decided to establish the first American volcano observatory, at KilaueaKilauea
, crater, 3,646 ft (1,111 m) deep, central Hawaii island, Hawaii, on the southeastern slope of Mauna Loa in Hawaii Volcanoes National Park. One of the largest active craters in the world, Kilauea has a circumference of c.
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. Construction began in 1912 on the Hawaiian Volcano Observatory; Jaggar retired as director in 1940. In 1916 what is now Hawaii Volcanoes National ParkHawaii Volcanoes National Park,
209,695 acres (84,926 hectares), on Hawaii island, Hawaii; est. 1916. The park contains two of the most active volcanoes in the world—Kilauea with its fire pit, called Halemaumau, and Mauna Loa with the active Mokuaweoweo crater on its
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 was established; Jaggar had advocated for it, and the observatory became part of it. In 1927–28 he led a National Geographic Society study of Aleutian Islands volcanoes. For this expedition he invented an amphibious vehicle, for exploring inaccessible beaches; his design was later adapted for use as a landing craft during World War II. In 1933 Jaggar used a Bosch-Omori seismograph to make the first accurate prediction of a tsunami. After his retirement, he was a research associate with the Univ. of Hawaii until his death.


See his autobiography (1956); J. Dvorak, The Last Volcano (2015).