National Geographic : 1928 Dec
FALCON, THE PACIFIC'S NEWEST ISLAND BY J. EDWARD HOFFMEISTER PROFESSOR OF GEOLOGY, UNIVERSITY OF ROCHESTER, N. Y ., AND HARRY S. LADD ASSISTANT PROFESSOR OF GEOLOGY, UNIVERSITY OF VIRGINIA ANDS as well as people have their ups and downs. It is doubtful, how ever, if any land has been built up and cut down so often within the recollec tion of man as has Falcon Island. Lo cated in the southwestern part of the Tonga, or Friendly, group of islands in the South Pacific, it has appeared, then disappeared from sight at least twice. In (ctober, 1927, another eruption occurred which again raised it high above the level of the sea and brought it to the attention of men the world over. Since that time newspapers of many countries have published articles concern ing its reappearance. Lavas have been re ported flowing down its sides and great clouds of ash and steam rising several thousand feet above it. These reports came at long intervals during the winter of 1927-28 and were made by [1. . S.S. Ia 1brnutm, the T. S. S. Tofua, and the S. S. Tutanikai, which on one or two occa sions passed close enough to obtain good views. At this time the writers were making plans to continue geological work begun in 1926 in Tonga and Fiji, under the sponsorship of the Bishop Museum of I onolulu. It was decided that, if it were physically possible, a trip should be made to Falcon Island and a landing effected. FALCON TIOCATEI) ON VOLCANIC LINI: The more exact location of Falcon Island is about latitude 20° 19' S. and longitude 175° 25' \. If one could ex amine a geological map of this general region, he would find that all the volcanic islands lie in a straight line which runs in a north-northeast and south-southwest di rection. Beginning with Mount Ruapehu, in North Island, New Zealand, through the Kermadec Islands, continuing through Ata (Pylstaart), Honga Tonga, Falcon, Tofua, Kao, Metis, Late, and Fanualai (Amargura), the volcanic islands of Tonga, and terminating in Samoa, this line includes one of the greatest chains of active and dormant volcanoes in the world (see map, page 760). It represents a line of weakness in the earth's crust and along it from time to time molten material is ejected. The world is made aware of these ejections only when the material reaches the surface and forms islands or shoals. It is very probable, however, that in many places along the line there are sub marine volcanoes of whose existence no knowledge has ever been obtained. If one were to predict where the next new island in this part of the world would appear, it would be fairly safe to say somewhere along this line. Practically all the other islands of the region are of nonvolcanic rock, chiefly limestone. A IIIID)-AND-SilFK ISLAND The island received its name when II. M. S. Falcon visited the spot in 1865 and reported a shoal. Twelve years later II. M. S. Sappho reported smoke to be issuing from the sea at the same position. In 1885 a submarine volcano burst suddenly into activity and built up a mound which, after a year of intermittent eruption, reached a height of at least 290 feet. In 1889, IT. M. S. Egqcria visited the island and Mr. J. J. Lister, an English geologist on board, made some careful observations. He found that during the four years since its formation the action of the sea had removed a large portion of the island, and that only about a third of the original mound remained. I le cal culated the maximum height of the island at that time to be 153 feet. Further observations were made by the British Admiralty in August, 1895. Fal con Island extended 800 yards in a north east-southwest direction and 700 yards in a northwest-southeast direction. It was nearly circular in form and only 40 feet above water.