Earthquake weather

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Earthquake weather is a type of weather popularly believed to precede earthquakes.

Contents

History

Since ancient times, the notion that weather can somehow foreshadow coming seismic activity has been the topic of much discussion and debate. [1] Geologist Russell Robinson has described "earthquake weather" as one of the most common pseudoscientific methods of predicting earthquakes. [2]

Aristotle proposed in the 4th century BC that earthquakes were caused by winds trapped in caves. Small tremors were thought to have been caused by air pushing on the cavern roofs, and large ones by the air breaking the surface. This theory led to a belief in 'earthquake weather', that because a large amount of air was trapped underground, the weather would be hot and calm before an earthquake. A later theory stated that earthquakes occurred in calm, cloudy conditions, and were usually preceded by strong winds, fireballs, and meteors. A modern theory proposes that certain cloud formations may be used to predict earthquakes; however, this idea is rejected by most geologists. [3] [4]

Background on earthquakes

An earthquake is caused by a sudden slip on a fault. Tectonic plates are always slowly moving, but they can get stuck at their edges due to friction. When the stress on the edge of a tectonic plate overcomes the friction, there is an earthquake that releases energy in waves that travel through the Earth's crust and cause the shaking that is felt. For example, in California, there are two plates, the Pacific plate and the North American plate. The Pacific plate consists of most of the Pacific Ocean floor, and also includes Baja California and the California coastline. The North American plate comprises most of the North American continent, including the inland parts of California, as well as parts of the Atlantic and Arctic Oceans' floors. The primary boundary between these two plates is the San Andreas Fault. The San Andreas Fault is more than 800 miles long and extends to depths of at least 10 miles. Many other smaller faults like the Hayward (San Francisco Bay Area) and the San Jacinto (Southern California) join with the San Andreas to form the San Andreas Fault Zone. The Pacific plate grinds northwestward past the North American plate at a rate of about two inches per year.

Earthquake cloud

Earthquake clouds are clouds claimed to be signs of imminent earthquakes. They have been described in antiquity: In chapter 32 of his work Brihat Samhita, Indian scholar Varahamihira (505–587) discussed a number of signs warning of earthquakes, including extraordinary clouds occurring a week before the earthquake. [5] In modern times, some scientists [ who? ] have claimed to accurately predict earthquake occurrences by observing clouds. [6] However, these claims have very little support in the scientific community. [7]

Psychology

It has been proposed by W. J. Humphreys that earthquake weather is not of geological causes, but merely a psychological manifestation. Humphreys argued that "the general state of irritation and sensitiveness developed in us during the hot, calm, perhaps sultry weather given this name, inclines us to sharper observation of earthquake disturbances and accentuates the impression they make on our senses, so that we retain more vivid memories of such quakes while possibly over-looking entirely the occurrences on other more soothing days". [8]

Scientific validity

Some recent research has found a correlation between a sudden relative spike in atmospheric temperature 2–5 days before an earthquake. It is speculated that this rise is caused by the movement of ions within the Earth's crust, related to an oncoming earthquake. Furthermore, this relative temperature change would not cause any single recognizable weather pattern that could be labelled "earthquake weather". [9] [10]

At the 2011 American Geophysical Union Fall Meeting, Shimon Wdowinski announced an apparent temporal connection between tropical cyclones and earthquakes. [11]

In April 2013, a team of seismologists at the Georgia Institute of Technology re-examined data from the 2011 Virginia earthquake using pattern-recognition software and found a correlation between Hurricane Irene's nearby passage and an unexpected rise in the number of aftershocks. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Earthquake</span> Sudden movement of the Earths crust

An earthquake – also called a quake, tremor, or temblor – is the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume.

<span class="mw-page-title-main">San Andreas Fault</span> Geologic feature in California

The San Andreas Fault is a continental right-lateral strike-slip transform fault that extends roughly 1,200 kilometers (750 mi) through the U.S. state of California. It forms part of the tectonic boundary between the Pacific Plate and the North American Plate. Traditionally, for scientific purposes, the fault has been classified into three main segments, each with different characteristics and a different degree of earthquake risk. The average slip rate along the entire fault ranges from 20 to 35 mm per year.

<span class="mw-page-title-main">Transform fault</span> Plate boundary where the motion is predominantly horizontal

A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone. A transform fault is a special case of a strike-slip fault that also forms a plate boundary.

In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousands of instrumentally detectable aftershocks, which steadily decrease in magnitude and frequency according to a consistent pattern. In some earthquakes the main rupture happens in two or more steps, resulting in multiple main shocks. These are known as doublet earthquakes, and in general can be distinguished from aftershocks in having similar magnitudes and nearly identical seismic waveforms.

<span class="mw-page-title-main">Juan de Fuca plate</span> Small tectonic plate in the eastern North Pacific

The Juan de Fuca plate is a small tectonic plate (microplate) generated from the Juan de Fuca Ridge that is subducting beneath the northerly portion of the western side of the North American plate at the Cascadia subduction zone. It is named after the explorer of the same name. One of the smallest of Earth's tectonic plates, the Juan de Fuca plate is a remnant part of the once-vast Farallon plate, which is now largely subducted underneath the North American plate.

<span class="mw-page-title-main">Parkfield, California</span> Unincorporated community in California, United States of America

Parkfield is an unincorporated community in Monterey County, California. It is located on Little Cholame Creek 21 miles (34 km) east of Bradley, at an elevation of 1,529 feet (466 m). As of 2007, road signs announce the population as 18.

<span class="mw-page-title-main">Los Angeles Basin</span> Sedimentary basin located along the coast of southern California

The Los Angeles Basin is a sedimentary basin located in Southern California, in a region known as the Peninsular Ranges. The basin is also connected to an anomalous group of east-west trending chains of mountains collectively known as the Transverse Ranges. The present basin is a coastal lowland area, whose floor is marked by elongate low ridges and groups of hills that is located on the edge of the Pacific plate. The Los Angeles Basin, along with the Santa Barbara Channel, the Ventura Basin, the San Fernando Valley, and the San Gabriel Basin, lies within the greater Southern California region. The majority of the jurisdictional land area of the city of Los Angeles physically lies within this basin.

<span class="mw-page-title-main">New Madrid seismic zone</span> Major seismic zone in the southern and midwestern United States

The New Madrid seismic zone (NMSZ), sometimes called the New Madrid fault line, is a major seismic zone and a prolific source of intraplate earthquakes in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri.

A volcano tectonic earthquake or volcano earthquake is caused by the movement of magma beneath the surface of the Earth. The movement results in pressure changes where the rock around the magma has a change in stress. At some point, this stress can cause the rock to break or move. This seismic activity is used by scientists to monitor volcanoes. The earthquakes may also be related to dike intrusion and/or occur as earthquake swarms. Usually they are characterised by high seismic frequency and lack the pattern of a main shock followed by a decaying aftershock distribution of fault related tectonic earthquakes.

<span class="mw-page-title-main">Parkfield earthquake</span> Series of earthquakes in California, US

Parkfield earthquake is a name given to various large earthquakes that occurred in the vicinity of the town of Parkfield, California, United States. The San Andreas fault runs through this town, and six successive magnitude 6 earthquakes occurred on the fault at unusually regular intervals, between 12 and 32 years apart, between 1857 and 1966. The latest major earthquake in the region struck on September 28, 2004.

<span class="mw-page-title-main">Cascadia subduction zone</span> Convergent plate boundary that stretches from northern Vancouver Island to Northern California

The Cascadia subduction zone is a 960 km (600 mi) fault at a convergent plate boundary, about 100–200 km (70–100 mi) off the Pacific coast, that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is capable of producing 9.0+ magnitude earthquakes and tsunamis that could reach 30 m (98 ft). The Oregon Department of Emergency Management estimates shaking would last 5–7 minutes along the coast, with strength and intensity decreasing further from the epicenter. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.

<span class="mw-page-title-main">Aseismic creep</span> Surface displacement along a geological fault without earthquakes occurring

In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "after-slip" days to years after an earthquake. Notable examples of aseismic slip include faults in California.

<span class="mw-page-title-main">Mendocino Triple Junction</span> Point where the Gorda Plate, the North American Plate, and the Pacific Plate meet

The Mendocino Triple Junction (MTJ) is the point where the Gorda Plate, the North American Plate, and the Pacific Plate meet, in the Pacific Ocean near Cape Mendocino in northern California. This triple junction is the location of a change in the broad tectonic plate motions which dominate the west coast of North America, linking convergence of the northern Cascadia subduction zone and translation of the southern San Andreas Fault system. This region can be characterized by transform fault movement, the San Andreas also by transform strike slip movement, and the Cascadia subduction zone by a convergent plate boundary subduction movement. The Gorda Plate is subducting, towards N50ºE, under the North American plate at 2.5–3 cm/yr, and is simultaneously converging obliquely against the Pacific plate at a rate of 5 cm/yr in the direction N115ºE. The accommodation of this plate configuration results in a transform boundary along the Mendocino Fracture Zone, and a divergent boundary at the Gorda Ridge. This area is tectonically active historically and today. The Cascadia subduction zone is capable of producing megathrust earthquakes on the order of MW 9.0.

<span class="mw-page-title-main">Newport–Inglewood Fault</span> Fault in Southern California

The Newport–Inglewood Fault is a right-lateral strike-slip fault in Southern California. The fault extends for 47 mi (76 km) from Culver City southeast through Inglewood and other coastal communities to Newport Beach at which point the fault extends east-southeast into the Pacific Ocean. The fault comes back on shore in the La Jolla area of San Diego and continues southward to downtown San Diego. In San Diego it is known as the Rose Canyon Fault. The fault can be inferred on the Earth's surface as passing along and through a line of hills extending from Signal Hill to Culver City. The fault has a slip rate of approximately 0.6 mm (0.024 in)/year and is predicted to be capable of a 6.0–7.4 magnitude earthquake on the moment magnitude scale. A 2017 study concluded that, together, the Newport–Inglewood Fault and Rose Canyon Fault could produce an earthquake of 7.3 or 7.4 magnitude.

<span class="mw-page-title-main">Submarine earthquake</span> Earthquake that occurs under a body of water, especially an ocean

A submarine, undersea, or underwater earthquake is an earthquake that occurs underwater at the bottom of a body of water, especially an ocean. They are the leading cause of tsunamis. The magnitude can be measured scientifically by the use of the moment magnitude scale and the intensity can be assigned using the Mercalli intensity scale.

<i>Earth Revealed: Introductory Geology</i> 1992 American TV series or program

Earth Revealed: Introductory Geology, originally titled Earth Revealed, is a 26-part video instructional series covering the processes and properties of the physical Earth, with particular attention given to the scientific theories underlying geological principles. The telecourse was produced by Intelecom and the Southern California Consortium, was funded by the Annenberg/CPB Project, and first aired on PBS in 1992 with the title Earth Revealed. All 26 episodes are hosted by Dr. James L. Sadd, professor of environmental science at Occidental College in Los Angeles, California.

<span class="mw-page-title-main">Wabash Valley seismic zone</span> Tectonic region in the Midwestern United States

The Wabash Valley seismic zone is a tectonic region located in the Midwestern United States, centered on the valley of the lower Wabash River, along the state line between southeastern Illinois and southwestern Indiana.

<span class="mw-page-title-main">Neenach Volcano</span> Extinct Miocene volcano cleaved in two by the San Andreas Fault in California

Neenach Volcano is an extinct Miocene volcano in the Coastal Ranges of California. After formation, the volcanic field was split by a fault in the San Andreas Fault Zone, and over the last 23 million years, the two halves of the volcano have moved about 195 miles apart.

This is a list of different types of earthquake.

The 1968 Borrego Mountain earthquake occurred on April 8, at 18:28 PST in the geologically active Salton Trough of Southern California. The Salton Trough represents a pull-apart basin formed by movements along major faults. This region is dominated by major strike-slip faults one of them being the San Jacinto Fault which produced the 1968 earthquake. The mainshock's epicenter was near the unincorporated community of Ocotillo Wells in San Diego County. The moment magnitude (Mw ) 6.6 strike-slip earthquake struck with a focal depth of 11.1 km (6.9 mi). The zone of surface rupture was assigned a maximum Modified Mercalli intensity (MMI) of VII.

References

  1. ↑ Goines, David Lance. "Earthquake Weather".
  2. ↑ Robinson, Russell (14 November 2002). Michael Shermer (ed.). The Skeptic Encyclopedia of Pseudoscience . ABC-CLIO. p.  96. ISBN   1-57607-653-9.
  3. ↑ "Is there earthquake weather?". FAQs – Earthquake Myths. United States Geological Survey (USGS).
  4. ↑ Curious cloud formations linked to quakes New Scientist, 11 April 2008. Accessed 2009-02-25.
  5. ↑ "A temblor from ancient Indian treasure trove?". The Times of India. 28 April 2001.
  6. ↑ Gup, G.; Xie, G. (2007). "Earthquake cloud over Japan detected by satellite". International Journal of Remote Sensing. 28 (23): 5375–5376. Bibcode:2007IJRS...28.5375G. doi:10.1080/01431160500353890. S2CID   129215702.
  7. ↑ "Curious cloud formations linked to quakes" . New Scientist. 11 April 2008.
  8. ↑ Monthly Weather Review. War Department, Office of the Chief Signal Officer. 1919. pp. 180–181.
  9. ↑ "Temperature rises hint at earthquake prediction". New Scientist. December 14, 2001.
  10. ↑ "Atmospheric temp spiked before Japan earthquake". Discover Magazine. May 23, 2011.
  11. ↑ "Link Between Earthquakes and Tropical Cyclones: New Study May Help Scientists Identify Regions at High Risk for Earthquakes". ScienceDaily. Retrieved 2011-12-28.
  12. ↑ "Hurricane may have triggered earthquake aftershocks". Nature. Retrieved 2013-04-22.
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