Since , earthquakes induced by wastewater disposal have become much more common in certain parts of the U. Although most of these earthquakes are too small to feel, some have been large enough to cause moderate structural damage and personal injury, such as the magnitude 5.
Beginning in , the U. Geological Survey has published annual one-year earthquake hazard forecasts [6] for the central and eastern United States that incorporate the risk of damage from induced earthquakes. The USGS earthquake catalog [2] can be used to find information and maps for earthquakes recorded around the world since the early 20th century.
Geological Survey 2 Earthquake Catalog U. Geological Survey. Skip to main content. But this skin is not all in one piece — it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other.
We call these puzzle pieces tectonic plates , and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults.
Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.
The tectonic plates divide the Earth's crust into distinct "plates" that are always slowly moving. Earthquakes are concentrated along these plate boundaries. While the edges of faults are stuck together, and the rest of the block is moving, the energy that would normally cause the blocks to slide past one another is being stored up. When the force of the moving blocks finally overcomes the friction of the jagged edges of the fault and it unsticks, all that stored up energy is released.
The energy radiates outward from the fault in all directions in the form of seismic waves like ripples on a pond. The cartoon sketch of the seismograph shows how the insrument shakes with the earth below it, but the recording device remains stationary instead of the other way around. Earthquakes are recorded by instruments called seismographs.
The recording they make is called a seismogram. The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. Instead the spring or string that it is hanging from absorbs all the movement. The difference in position between the shaking part of the seismograph and the motionless part is what is recorded. When the force of movement finally overcomes the friction, sections of the crust suddenly break or become displaced, releasing the pent-up pressure in the form of seismic waves.
This is a naturally occurring earthquake, sometimes referred to as a tectonic earthquake. While tectonic earthquakes can occur at any location around the world, the majority of large earthquakes—about 80 percent—occur at the circum-Pacific seismic belt found along the rim of the Pacific Ocean. Two other regions regularly exhibiting earthquakes include the Alpide belt, extending along the southern margin of Eurasia through the Himalayan Mountains, Sumatra, and Java; and the Mid-Atlantic Ridge running along the floor of the Atlantic Ocean.
It involves the injection of large volumes of water, sand, and chemicals under high pressure into a bedrock formation to create new fractures in the rock or increase the size, extent, and connectivity of existing fractures, leading to more permeability. On rare occasions, fracking can lead directly to earthquakes. More frequently, earthquakes are induced by the disposal of waste water associated with the oil production into underground wells. The causes of earthquakes and the different types of tectonic boundaries and faults on which they usually occur.
Where do earthquakes occur? Discovering Geology — Earthquakes. You may also be interested in:. Earthquakes Earthquakes are among the most deadly natural hazards. How are earthquakes detected? How do earthquakes affect people? What causes earthquakes? Was this page helpful? Yes No. Close Button.
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