NATURAL PHENOMENA 



ranges of detection. Less than 30 years ago it was widely believed 

 on the basis of visual observations that most, if not all, sporadic 

 meteor's were of interstellar origin. 



The development of photographic equipment has enabled astrono- 

 mers to accurately compute the paths, entering velocities through 

 the atmosphere, and the radiant points of meteors. In addition, the 

 deceleration of meteors by air resistance can be evaluated accurately 

 enough to indicate the density of the upper atmosphere. 



Another breakthrough was scored soon after World War 11, 

 when radar observations began in England and Canada. When a 

 meteoric object traverses the earth's atmosphere, a cylinderical 

 column of ionized gas is produced which is a good reflector for radio 

 waves. The echo is strongest from the point where the column is 

 perpendicular to the line of sight. With a three-station system, it is 

 possible to obtain excellent determinations of velocities and radiants 

 of individual meteors. 



Radar techniques can record meteors several magnitudes too 

 faint to be photographed. Furthermore the radar observations can 

 be continued around the clock, irrespective of daylight or clouds. 



NATURE'S LIGHTHODSES 



On the island of Tof ua, in the Tonga or Friendly Islands of the 

 South Central Pacific Ocean, an area noted for its volcanic activity, 

 is an extremely active volcano which is used as an aid to navigation. 

 By day it emits smoke for 5 minutes out of every 10 and by night 

 it displays flaring flames. Although there are other volcanic islands 

 in that area that spew forth fire and smoke, none have the regularity 

 of Tofua. Captain Bligh observed this phenomenon while adrift in 

 the Bounty's longboat, and he recorded it in his logbook on April 28, 

 1789. 



Another of nature's lighthouses in the Pacific has been used as 

 an aid to navigation for years. This volcano's name is Izalco and its 

 location El Salvador. Blazing regularly every eight minutes, it was 

 once known as the "Lighthouse of the Pacific". 



NATURE'S TOWBOAT 



In the Dardanelles, below the surface current, a more dense sub- 

 surface counter-current enables fishermen to give their boats a tow 

 against the surface current by lowering their nets into the deeper 

 sub-surface current. 



In the Black Sea the precipitation and runoff exceed the evapo- 

 ration, thus giving rise to a low density, low salinity, surface layer. 

 As a result, the surface waters of the Black Sea flow out through 

 the Bosporus and the Dardanelles, whereas the Mediterranean waters 

 flow into the Black Sea along the bottom, thus explaining the above 

 phenomenon. 



A REEF THAT EXPLODED 



In Erin Bay, about 1V4 miles off the southwest coast of Trinidad, 

 a reef, known as Despatch Reef, has an interesting and explosive 

 origin. On November 11, 1911, a submarine disturbance caused an 

 island about 8 acres in extent to be raised 12 feet above sea level 

 where there had previously been 6 to 10 feet of water. Fishermen 

 who observed the phenomenon noticed that several days before the 

 eruption the sea in the vicinity was churning violently and the air 

 smelled of sulphur. 



At 6 P.M. on the 11th a rumbhng noise as of distant thunder was 

 heard coming from a mound that had risen above the surface of the 

 sea and which was emitting dense black clouds of smoke billowing sky- 

 ward. The clouds were followed by a great blaze of flame rising 

 300 or more feet in the air. The color of the flame was reported 

 blue to straw-colored and the duration was from 7 to 10 minutes. 

 The flame was visible in Port-of-Spain more than 50 miles away 

 where residents assumed there had been an explosion in developing 

 oil fields of the area. The newly arisen island existed for several 

 months, but the wind and eroding action of the the sea soon worked 

 the apparently soft structure back into the sea. Today, on Oceano- 

 graphic Office Chart No. 1963, there appears only the notation of a 

 submerged reef in the vicinity of Despatch Reef. 



Subsequent investigation of the phenomenon by Mr. Ralph Arnold, 

 an American geologist and petroleum engineer, suggests the follow- 

 ing sequence of events and theory of origin. 



No recent volcanic rocks or other evidence of true volcanic 

 activity are known on Trinidad. The porous sand beds and lenses 



containing petroleum gas, in many occurrences under enormous 

 pressure, are associated with oil-bearing strata, especially along the 

 anticlines or lines of disturbance. Mud volcanoes and pitch cones 

 are found inland of Erin Bay and yield gas and muddy and oily 

 water discharging continuously, intermittently, and occasionally, 

 briefly and violently. 



The appearance of the island was first heralded by an escape of 

 gas from the apex of the anticline or line of disturbance coincident 

 with the reef in Erin Bay. This was followed by the upwelling of 

 the reef accompanied by a fracturing of the rocks and rapid eject- 

 ment of mud with minor amounts of fragmental material through 

 a more or less well defined vent or crater. Two cones 20 to 30 feet 

 high rose above the surface of the island and served as vents at the 

 time of the explosion. During the height of the eruption when large 

 quantities of hard rock fragments were being ejected, sparks were 

 probably formed by the striking together of some of the rocks, and 

 the petroleum gas thus ignited. 



Following the destruction of the main cone several mud flows 

 continued to be pushed upward from below the surface. Gas con- 

 tinued to escape from numerous small vents on the island but 

 lessened as several days passed. This resembled large gas volcanoes 

 in behavior which erupt periodically as the subterranean gas pres- 

 sures build up, eject, and subside. 



The presence of oil sand in the ejected material on the island 

 and the presence of petroleum gas odor clearly demonstrated that 

 source of gas was from the oil- and gas-bearing strata which under- 

 lies that area of Trinidad. In summary, the explosive origin of 

 Despatch Reef was the result of a violent eruption of petroleum gas. 

 The phenomenon was clearly non-volcanic in origin. The unusual 

 features of this gas volcano were its large size as compared with 

 similar cones of this character, its submarine origin, and the fact 

 that the gas which caused the eruption ignited during its escape. 



RED TIDE 



In recent years this phenomenon has occurred off the coasts of 

 several countries including India, Australia, Peru, and the United 

 States. This scourge to sea life is caused by a small organism known 

 as a dinoflagellate. Although classified among the algae, the power 

 of movement places the creature between the animal and vegetable 

 kingdoms. 



Under suitable environment these organisms reproduce so 

 rapidly that as many as 60 million may be contained in a quart of 

 sea water, producing a deadly effect on other sea life. In vast 

 numbers they give the water a reddish color but observations indi- 

 cate other colors such as yellow, yellow-brown, or olive-green occur. 



Scientists have advanced the theory that after heavy rains the 

 run-offs in certain coastal regions contains phosphates and vitamin 

 B12 which together with a lowering of the salinity and with 

 favorable temperature enable the dinoflagellates to multiply at in- 

 credible rates. 



Fish killed by red tide 



It is suspected that these creatures secrete a poison as deadly as 

 botulinum, which is claimed to be the most poisonous substance 

 known. This secretion kills fish, turtles, and other marine life; 

 causes inflamation of lungs and throats to humans swimming in such 



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