Hot springs provide hints of eruption.People living in the shadow of a dormant volcano A dormant volcano is a volcano which is not currently active (that is, not erupting nor showing signs of unrest), but is believed to be still capable of erupting. This contrasts with an extinct volcano, where it is believed that no eruptions will occur for the foreseeable future. may want to keep tabs on some of the hot springs in their region. On the Caribbean island of Montserrat, underwater thermal springs just off the coast gave off clues of mounting danger before the Soufriere Hills Soufrière Hills A volcano, 915 m (3,002 ft) high, on southern Montserrat in the Leeward Islands of the West Indies. It began erupting in 1995 for the first time in recorded history, causing the evacuation of thousands of residents. Volcano erupted there in 1995, according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. British researchers. While studying hot springs in the Caribbean, the team fortuitously for·tu·i·tous adj. 1. Happening by accident or chance. See Synonyms at accidental. 2. Usage Problem a. Happening by a fortunate accident or chance. b. Lucky or fortunate. surveyed three sets on Montserrat in January 1995. Six months later, on July 18, the volcano reawoke from more than 3 centuries of slumber, starting a cycle of eruptions that has devastated dev·as·tate tr.v. dev·as·tat·ed, dev·as·tat·ing, dev·as·tates 1. To lay waste; destroy. 2. To overwhelm; confound; stun: was devastated by the rude remark. the southern two-thirds of the island over the last 2 years (SN: 8/16/97, p. 101). David S. Cronan of the Imperial College of Science, Technology, and Medicine in London and his colleagues returned to measure the springs immediately after the July eruption and again in December 1995. The two sets of hot springs on land showed no systematic changes during the period, but the springs located only 50 meters from the beach displayed a dramatic increase in activity. In July, concentrations of iron averaged 300 times the value measured in January. Manganese manganese (măng`gənēs, măn`–) [Lat.,=magnet], metallic chemical element; symbol Mn; at. no. 25; at. wt. 54.938; m.p. about 1,244°C;; b.p. about 1,962°C;; sp. gr. 7.2 to 7. concentrations had increased by 40 times and arsenic by 60 times, the researchers report in the Aug. 19 Eos. Because Cronan and his team made their second set of measurements after the eruption, they cannot tell for certain whether the metals increased before or during the July blast. Some evidence, however, points to the changes occurring before the volcano blew. When the scientists made measurements during subsequent eruptions in December, they saw relatively stable metal concentrations, A suggesting that the blasts themselves do not alter the fluids substantially. Cronan suggests that molten rock rising up under the volcano in early 1995 helped heat seawater seawater Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. circulating through the seafloor. The hot fluids leached elements from the crust faster than normal, leading to greater concentrations of dissolved metals in the water spewing from the submerged hot springs. |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion