Gakkel Ridge magnitude 5.8 and 5.1 earthquakes (7:01 & 7:43 AM, 21 May 2022) 2 : 無料・フリー素材/写真
Gakkel Ridge magnitude 5.8 and 5.1 earthquakes (7:01 & 7:43 AM, 21 May 2022) 2 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | This is a seismogram from the Ny-Alesund seismic station in Spitzbergen. The prominent noise at left on the 7:00 line was caused by a magnitude 5.8 offshore earthquake along the southwestern part of the Gakkel Ridge in the Arctic Ocean. The quake hit at 7:01 AM, local time, on 21 May 2022. The epicenter was about 353 kilometers northeast of North Greenland's Cape Eilor Rasmussen (= far-eastern Peary Land). Shaking resulted from normal faulting along a ~northeast-southwest striking fault zone. A magnitude 5.1 aftershock occurred nearby about 42 minutes later (= the noise at right on the 7:00 line).The Gakkel Ridge is a mid-ocean ridge in the Arctic Ocean that formed by tectonic divergence between the North American Plate and the Eurasian Plate. Seafloor spreading along the ridge is very slow.--------------------------------Info. at:earthquake.usgs.gov/earthquakes/eventpage/us6000hmv1/exec...andearthquake.usgs.gov/earthquakes/eventpage/us6000hmv8/exec...anden.wikipedia.org/wiki/Gakkel_Ridge--------------------------------An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989. |
| 撮影日 | 2022-05-22 02:24:48 |
| 撮影者 | James St. John |
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