Indonesian Tsunami Was Powered by a Deadly Combo of Tectonics and Geography - Scientific American
Tsunami wave field in the Bay of Bengal one hour after the earthquake. occurred along a tectonic subduction zone in which the India Plate. What Causes a Tsunami - by balamut.info in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces. The friction between the subducting plate and the overriding plate is enormous. Caught in the middle: Lombok and Bali are exposed to earthquake and tsunamis risk due to a tectonic plate boundary to the south, but also a.
- How Plate Movement Affects Earthquakes, Tsunamis & Volcanic Eruptions
- Indonesian Tsunami Was Powered by a Deadly Combo of Tectonics and Geography
- Ocean STEMulation: Tsunamis and Plate Tectonics
At transform boundaries, two plates slide past each other. The San Andreas fault in California occurs at this type of plate boundary. At divergent boundaries, plates move away from each other.
The Mid-Atlantic Ridge is a divergent boundary. At convergent boundaries, plates move toward each other. Artist's cross section illustrating the main types of plate boundaries. Vigil from This Dynamic Planet -- a wall map produced jointly by the U.
How are tsunamis generated? | Earth Contemporary Controversies in the Earth Sciences
Geological Surveythe Smithsonian Institution, and the U. Earthquakes and tsunami generation Earthquakes happen when plates move with respect to each other because the friction and stress at the edges of plates prevents them from slipping smoothly at their boundaries.
For an earthquake to generate a tsunami you need: Water Vertical motion If an earthquakes happens far away from a body of water, it probably won't disturb the water too much.
Therefore, no tsunami is expected. Next you need a vertical disturbance. You have a bathtub full of water and a hard-backed book. If you dip the book into the bathwater spine-first and move the book back and forth longways, what do you observe?
What Causes a Tsunami?
Not much, except you've ruined your book. Now if you hold the book with its flat side on the surface of the water and move the book up and down in the water, you should generate some big waves as the vertical motion you've imposed on the water column is transferred to horizontal motion as the wave travels away from the source.
This is basically how a tsunami is generated. Do we expect California to "fall into the ocean" as in the cartoon I drew? Think about why or why not based on material you just read Click for answer We probably wouldn't expect a big tsunami. Remember the three types of plate boundaries. Earthquakes at transform boundaries, like the San Andreas fault, involve hardly any vertical motion.
This heaving of the seafloor forces ocean water upward and outward. But strike-slip faults can also generate tsunamis through a couple different mechanisms that geologists have been evaluating for this event, in real time on Twitter and other social media platforms.
Such occurrences have long been known to cause massive tsunamis; a rockslide triggered by a magnitude 7. It sent water roaring up mountainsides to reach elevations of 1, feet, and remains the largest tsunami recorded in modern times. Another possibility is the movement of the fault itself caused the tsunami. Although the fault moved horizontally and not vertically, the steep slopes and other unique features on the floor of Palu Bay could have pushed water in front of them as they moved during the earthquake.
How are tsunamis generated?
Researchers at the Karlsruhe Institute of Technology in Germany have done a preliminary study with a tsunami model, and found the lateral movement of the fault and the topography of the bay would be enough to generate a tsunami the size of the one that hit Palu. Neither possibility precludes the other. The Indonesian earthquake caused "liquefaction" in areas near Palu.
Below western Indonesia the Indo—Australian Plate is shoved below the Eurasian Plate, occasionally creating the classic megathrust earthquakes that can generate huge tsunamis just as the magnitude 9. But in eastern Indonesia, where Sulawesi is located, the Indo—Australian Plate is topped by continental crust that does not subduct —so it is simply ramming headlong into the crust of the Eurasian Plate, fracturing it.