Mid-Atlantic Ridge magnitude 6.2 earthquake (2:38 PM, 9 October 2022) 3

This seismogram is from the Riachuelo seismic station in Brazil. The noise is from a magnitude 6.2 offshore earthquake that hit the central Mid-Atlantic Ridge at 2:38 PM, local time, on 9 October 2022. The quake was produced by right-lateral slip along an ~east-west striking transform fault.

The Mid-Atlantic Ridge is a classic example of a mid-ocean ridge, where two tectonic plates diverge (separate) and new oceanic crust forms - this is called "seafloor spreading". In this case, the South American Plate and the African Plate are moving away from each other. This quake occurred along the Romanche Transform Fault, which is near the Equator between Brazil (South America) and Liberia (Africa). Mid-ocean ridges are offset by numerous short to long transform faults - this results in a zig-zag pattern in map view.

This quake occurred during a Moon-Earth-Sun alignment.
--------------------------------
Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000isau/exec...
and
en.wikipedia.org/wiki/Romanche_Trench
and
en.wikipedia.org/wiki/Mid-Atlantic_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.

Some rights reserved

Taken on: October 9, 2022

Tags:

Mid-Atlantic

Ridge

6.2

earthquake

earthquakes

quake

quakes

October

2022

Romanche

Transform

Fault

faults

transforms $Everybody's photos tagged with fracture$ fracture

zone

zones « less

Sets appears in: • 2022 Earthquakes • Mid-Atlantic Ridge Earthquakes more » • Magnitude 6+ Earthquakes • Earthquakes « less

Stats: 309 views

go back

Link to this photo view:
Link to this photo large view: