Aegean Sea earthquake swarm (1 to 5 February 2025) : 無料・フリー素材/写真
Aegean Sea earthquake swarm (1 to 5 February 2025) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | This map (provided by the United States Geological Survey) shows a cluster of earthquakes from 1 to 5 February 2025 in the Aegean Sea. The activity is northeast and east of the island of Santorini, which is in the southern Cyclades Islands north of Crete and between Greece and Turkey. Clusters of earthquakes with no mainshock are called "swarms". The largest event so far was magnitude 5.3. Hundreds of quakes have occurred - the map only shows the 69 strongest events. Four of these were magnitude 5+. The rest were magnitude 4+. The swarm commenced in late January 2025, but the stronger events started on 1 February. The frequency and strength of the seismicity have alarmed local residents.--------------------------------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 | 2025-02-05 18:55:40 |
| 撮影者 | James St. John |
| タグ | |
| 撮影地 |