• Question: how are earthquakes made?

    Asked by danielhor to Shane, Maria, Karen, Gabriele, Angela on 15 Nov 2013.
    • Photo: Angela Stevenson

      Angela Stevenson answered on 15 Nov 2013:

      Earthquakes happen when two blocks of the earth suddenly slip past one another. So why does this slip happen? The earth has four major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet… this skin is not just one piece, it has many many pieces. Imagine a jigsaw puzzle covering the surface of the earth – that’s what this think skin looks like – we call these pieces tectonic plates. These puzzle pieces move around slowly, sliding past and bumping into each other. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving and eventually the plate has moved far enough that the edges ‘unstick’ from each other and boom! there’s an earthquake. Excellent question again Daniel. Great job!

    • Photo: Karen McCarthy

      Karen McCarthy answered on 15 Nov 2013:

      Earthquakes are caused by the movement of tectonic plates on the Earths surface. All the continents are resting on these plates, which are always slowly moving. If two plates hit off each other, the energy released by this collision can cause earthquakes on Earth.

      The Richter scale was a scale designed to measure the magnitude of an earthquake, aka the amount of energy it released. It is a logrithmic scale, meaning the difference between each whole number is tenfold!

      The worst earthquake ever was recorded in Chile in 1960, and measure 9.2 (!!) on the Richter scale!

    • Photo: Shane Mc Guinness

      Shane Mc Guinness answered on 18 Nov 2013:

      Great answers guys. That’s covered most of it. Though the majority of earthquakes happens when something called ‘subduction’ happens, when a bit of a tectonic plate slides under another one, causing the lower one to bend and a bit suddenly snaps off.
      But earthquake don’t just happen along these edges of tectonic plates. They also happen along things called faults, which are large cracks in these plates.
      Finally, earthquakes can also be caused by human disturbances to the underground, through mining, water pumping or oil drilling.

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