Question: What is the connection between earthquakes and tectonic plates?

Asked by 6fkabrea to Anna, Daniel, Denise, Jesse, Rehemat on 18 Jun 2014.

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  1. Photo: Jesse DavenportJesse Davenport
    answered on 18 Jun 2014:

    Hello 6fkabrea, this relationship became pretty well established with the development of plate tectonic theory in the 1970s. If you look at a map and plot where all earthquakes happen, you’ll find that they are in pretty specific places (of course, there are exceptions to this, but I won’t get into that). These areas where earthquakes occur are where two different plates are interacting. For example, just east of Japan, the Pacific Plate is diving beneath the plate Japan rests upon, and Japan is slowly moving closer to the U.S. This subduction zone interaction is the reason for large earthquakes that occur in Japan.

    Another example of the interaction of plates that cause earthquakes is a convergent margin or when two plates collide with each other such as the case between the Indian plate and Asian plate to form the Himalayas. This area is still colliding today, still pushing the mountains higher. Another example is the San Andreas Fault in California, where two plates are interacting in a strike-slip manner. The plates lock together for many years building up a large amount of stress and eventually something triggers the release of stress and an earthquake occurs.

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  2. Photo: Daniel Lao DavilaDaniel Lao Davila
    answered on 18 Jun 2014:

    The tectonic plates move towards, away or past each other at plate boundaries. This movement will concentrate a lot of energy as rocks are deformed. When rocks break, they will release an incredible amount of energy and will shake the ground, what we call earthquakes. Most of the earthquakes in the Earth occur at plate boundaries due to the ongoing movement of the plates. If we know where the plate boundaries are, then we also know where most of the earthquakes occur.

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  3. Photo: Rehemat BhatiaRehemat Bhatia
    answered on 18 Jun 2014:

    Great question, and I think Jesse and Daniel have already summed up the answer very nicely.
    The effect of the earthquake on its surroundings depends on the depth at which it occurs – a shallow quake will cause more damage as its closer to the surface of the earth whilst a deeper quake will cause less damage as its further away from the surface of the earth.
    An earthquake which occurs at a normal or reverse fault can cause land to be uplifted whilst an earthquake which occurs at a strike slip fault can cause land to shift in a sideways motion – for example in San Francisco a fence was broken and moved up relative to where it was previously as that was how far the land was displaced by the stress release from the earthquake. See all of our answers to how faults work on this page – https://earthj14.imageoscientist.eu/2014/06/13/what-are-the-different-types-of-faults/

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  4. Photo: Denise De GaetanoDenise De Gaetano
    answered on 22 Jun 2014:

    Hi 6fkabrea,

    In 1969, Muawia Barazangi and James Dorman published the locations of all earthquakes which occurred from 1961 to 1967. Most of the earthquakes are confined to narrow belts and these belts define the boundaries of the plates. The interiors of the plates themselves are largely free of large earthquakes, that is, they are aseismic. There are notable exceptions to this. An obvious one is the 1811-1812 earthquakes at New Madrid, Missouri, and another is the 1886 earthquake at Charleston, South Carolina. As yet there is no satisfactory plate tectonic explanation for these isolated events; consequently, we will have to find alternative mechanisms. (Source: USGS)

    Hope this helps! 🙂

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  5. Photo: Anna RabittiAnna Rabitti
    answered on 25 Jun 2014:

    Hi 6fkabrea,
    I think all the other scientists already gave nice answers to your question.
    I can add this link
    http://www.iris.edu/seismon/
    where you can see in real time all the earthquakes that are happening, or that happened in the past.
    I am sure you are able to recognize the boundaries of the different tectonic plates if you look at the locations of the earthquakes, so you can see the connection yourself!

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