Sumatran earthquakes in April were part of tectonic plate breakup

September 27, 2012 INDONESIA - Planet Earth may be 4.5 billion years old, but that doesn’t mean it can’t serve up a shattering surprise now and again. Such was the case on April 11 when two massive earthquakes erupted beneath the Indian Ocean off the coast of the Indonesian island of Sumatra, far from the usual danger zones. Now scientists say the seafloor ruptures are part of a long suspected, yet never before observed, event: the slow-motion splitting of a vast tectonic plate. The first of the quakes, a magnitude 8.7, was 20 times more powerful than California’s long anticipated “big one” and tore a complex network of faults deep in the ocean floor. The violence also triggered unusually large aftershocks thousands of miles away, including four off North America’s western coast. “It was jaw-dropping,” said Thorne Lay, a professor of Earth and planetary sciences at UC Santa Cruz. “It was like nothing we’d ever seen.” At first, Lay wondered whether the computer code he used to analyze earthquakes was wrong. Eventually, he and other scientists realized that they had documented the breakup of the Indo-Australian plate into two pieces, an epic process that began roughly 50 million years ago and will continue for tens of millions more. Lay and other scientists reported their findings online Wednesday in the journal Nature. Most great earthquakes occur along plate borders, where one plate dives beneath the adjoining plate and sinks deep into Earth’s mantle, a process called subduction. The April 11 quakes, however, occurred in the middle of the plate and involved a number of strike-slip faults, meaning the ground on one side of the fault moves horizontally past ground on the other side. Scientists say the 8.7 main shock broke four faults. The quake lasted 2 minutes and 40 seconds — most last just seconds — and was followed by a second main shock, of magnitude 8.2, two hours later. Unlike the magnitude 9.1 temblor that struck in the same region on Dec. 26, 2004, and created a deadly tsunami, the April 11 quakes did not cause similar destruction. That’s because horizontally moving strike-slip faults do not induce the massive, vertical displacement of water that thrust faults do on the borders of plates. The type of interplate faults involved in the Sumatran quakes are the result of monumental forces, some of which drove the land mass of India into Asia millions of years ago and lifted the Himalayan Mountains. As the Indo-Australian plate continues to slide northwest, the western portion of the plate, where India is, has been grinding against and underneath Asia. But the eastern portion of the plate, which contains Australia, keeps on moving without the same obstruction. That difference creates squeezing pressure in the area where the quakes occurred. The study authors say that over time, as more quakes occur and new ruptures appear, the cracks will eventually coalesce into a single fissure. “This is part of the messy business of breaking up a plate,” said University of Utah seismologist Keith Koper, senior author of one of the studies. “Most likely it will take thousands of similar large quakes for that to happen.” The quakes were also notable for triggering powerful aftershocks thousands of miles away. Though major quakes have been known to trigger aftershocks at great distance, they are usually less than 5.5 in magnitude. The April earthquakes triggered 11 aftershocks that measured 5.5 or greater in the six days that followed, including a magnitude 7. Remote shocks were felt 6,000 to 12,000 miles from the main quakes. Fred Pollitz, a geophysicist with the U.S. Geological Survey in Menlo Park, Calif., and lead author of one of the studies, said the quakes were extremely effective in transmitting seismic wave radiation around the world. Though Pollitz said the magnitude of the larger Sumatran quake is No. 10 on the list of quakes since 1900, no other temblor has triggered so many strong aftershocks so far away. “It’s the most powerful earthquake ever in terms of capability of putting stress on other fault zones around the world,” he said. –LA Times
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This entry was posted in 2012, Civilizations unraveling, Earth Changes, Earth Watch, High-risk potential hazard zone, Lithosphere collapse & fisssure, Planetary Tremor Event, Potential Earthchange hotspot, Seismic tremors, Signs of Magnetic Field weakening, Time - Event Acceleration, Volcanic Eruption, Volcano Watch. Bookmark the permalink.

22 Responses to Sumatran earthquakes in April were part of tectonic plate breakup

  1. Barry Wright says:

    All these earthquakes and volcanoes makes me think more and more about planet x crossing our planet and sun on October 17… Alvin do you really think this will happen? I’ve read that NASA has changed it’s name to comet something and will no longer call it nebula, to create confusion amongst us…

  2. Emanni says:

    Am I reading this right?

    Tsunami buoy Station 53046 – South Bali (northwest of Australia / south of East Java) is reading that the sea floor has risen 300 meters between September 24th and September 27th?

    • Dave Neff says:

      Wouldn’t this have generated a Tsunami if 1000 ft of water was uplifted? Or was it too gradual? I confess my ignorance in this subject.

      • IM

        The April earthquakes off the coast of Indonesia were lateral strike-slip quakes. A mega-thrust earthquake would be a vertical displacement of land, and consequently would lead to a displacement of water. This would generate a tsunami. A lateral strike-slip is when two land masses slide pass each other in horizontal fashion (see figure)…therefore, there is no displacement of water. This may have been one of the luckiest days in Indonesian history- people should count their blessings.

  3. Check the buoy off South Bali. Water column shrank 377 meters in the last month! Wasn’t there a similar problem at Banda Aceh? Maybe Lemuria will be making a comeback?

  4. EP_Sh says:

    Sooner or later, this earth is gonna tear apart !

  5. Joseph t. Repas says:

    Hi Alvin! Would this be like the Madrid fault in the central USA ? and do any scientists think that the Madrid fault could pound the Eastern USA again soon? Thanks!

    • IMG
      Yellowstone eruptions appear to occur when the North America plate slides over the hotspot.

      No, it’s a little different but the Mardrid fault is an active system and I expect a lot of activity out of it in the future because the changes occurring to the planet right now will gravely impact tectonic plates and when the North American plate sees more activity- not only will New Madrid become more kinetic but Yellowstone could be agitated as well.

      • Joseph t. Repas says:

        Thanks Alvin! The world is slowly learning that there is nothing solid on this planet but the promises of Christ.

  6. Dave says:

    wonder if this is connected to buoy 53046 between the Austrialia and Indonesian ..look s like it is down 1000 water column height…

  7. Marshallrn says:

    So this is just the beginning!? Sounds like as those “thousands” of quakes occur in the years to come the faults of the world are going to build and build pressure, slowly releasing their pent up power on the inhabitants located around these stressors. I am happy to be living in Northern California between two of the most feared fault lines for the 21st century.

  8. niebo says:

    “Most powerful earthquake ever in terms of. . .stress put on other fault zones….” A spark for the powderkeg?

  9. BDM says:

    Made me wonder, how do they know it is a plate breakup, new faults making a distinct “line” across a vast area? I didn’t see anyone name the new plate so hereby name it… BDM’s Plate.

  10. Irene C says:

    Not that I like to see this happening, but I’m glad they are acknowledging it. I do believe we have discussed this here. So many of these faults are interconnected.

  11. neeka says:

    Sooo is that a sign of earths crust. starting to displace? so much activity with sink holes, quakers , unexplained tremors. Doesn’t sound good to me.

  12. Michele B says:

    And up pops another number 11.

  13. tonic says:

    Just wonder how a planet 4.5 billion years old, is still so hot, and still capable of releasing energy of this proportion. Mars is dead, or so we are told.
    But the Earth is alive and well, and just carries on as normal, and just refuses to stop evolving.
    It really is an amazing planet.
    When this plate eventually snaps, the consequences, mind boggling.

    • AWM says:

      Change is coming and it will be like nothing in earth’s recent collective histoy,
      The Bible,it’s all there.

      • tonic says:

        The bible it’s all there………………..for you yes. I have been unfortunate in my education of the bible. ……..I envy you
        My answers it seems, will be life learnt

      • Joseph t. Repas says:

        It’s not too late Tonic! The Good News is available for reading and the Holy Spirit is available for explanation. The Bible is also available in audio form and on radio and TV. Of course all of the Bible’s lessons are taught to us through life’s events, both painful and joyful. When you read or listen to the Bible ask God’s Holy Spirit to guide you in the message. He wants to feed you, you are His child. What good Father would not want to feed their children nourishing food? Be blessed!

  14. tonic says:

    Joseph, Thank you for this kind reply.
    I was “trained” as a catholic, but, stupid as it sounds became interested in the Bible after reading Robinson Cruseo at a young age! I know, sounds pretty ridiculous, but this was the case. I wanted to find out why he found comfort in reading this book.
    Many, many, and many years later, I have reached the conclusion that “self taught” does not work in this case. You need a teacher.
    Why? Because without teaching, (interpetration is an open book) the challenges people face in life, can only be handled by who and what they are made of.
    There are many people across the globe who lack teaching, me included. You see….. it’s not my fault, or theirs, it’s just the way life turned out.

    • Joseph t. Repas says:

      Thank you tonic. I commend you for your wisdom of knowing that you want to be taught the Holy Scriptures and that you need to have someone teach you it’s meaning. Keep searching my friend and always ask the Holy Spirit to give you discernment for truth. If I may, I would like to suggest listening to Charles Stanley. You can find him on the internet, radio, and television and although he is not the only preacher true to the Bible I have found him to be consistently encouraging and accurate to the Word. Be blessed.

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