100-metre waves are a threat today

• Autores: Joshua Sokol
• Localización: New scientist, ISSN 0262-4079, Nº. 3042, 2015, pág. 12
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • With waves taller than 100 meters, it's no wonder they are called megatsunamis. After part of Cape Verde's Fogo volcano fell into the sea around 70,000 years ago, a wave 170 meters tall slammed into nearby Santiago island, now home to over a quarter of a million people. That's the conclusion of work by Ricardo Ramalho, now at the University of Bristol, UK, and his team at Columbia University in New York. They say that the volcano has since grown back to its pre-disaster proportions and may be in for another catastrophic collapse. Ramalho noticed huge boulders scattered across Santiago's landscape, as high as 220 meters above sea level and 650 meters from the coastline. Some weigh more than 700 tonnes and are made of rock similar to that at the shore--suggesting they were deposited by a large wave. By combining data on the boulders with the pattern of rock sediments at lower altitudes, his team estimated the height, path and date of the wave. That date matched with Fogo's partial collapse, some 73,000 years ago. Ramatha's team says the event triggered a wave up to 170 meters tall, that traveled 55 kilometers to the shores of Santiago