Chile Earthquake & Tsunamis – Plus 40s Ahead

***Watch WISN 12 News for the latest forecast information!***

Thank you for spending part of your weekend with us on the Weather Watch 12 blog!  Remember…you can still view the long range March forecast…just check the blog entry right below this one.

Once again a very strong earthquake struck, this time in the Country of Chile.  The earthquake had a magnitude of 8.8 on the Richter Sclale.  Believe it or not this earthquake was one of the strongest ever recorded in the world, and 500 times stronger than the Haiti quake!  The Chile earthquake formed on the ‘Pacific Ring of Fire’ along the Peru-Chile Trench.  Below is a look at the entire Ring of Fire…all of these fault lines can cause significant earthquakes.

The big concern right after the earthquake was the potential for a devastating tsunami across the Pacific…including in Hawaii.  A Tsunami Warning was issued 10+ hours in advance.  It turns out and thankfully so, the Tsunami only created slightly higher water levels around the island chain when it passed by.

Since we have now had 2 very large earthquakes occur in the past two months, let’s take a look at how a Tsunami forms.  The image below shows the center of an earthquake labeled by the red circles.  The shifting of the earth caused a push up and down in the water…creating an upward wave.  This is the start of a Tsunami.

A more detailed explanation is below including 3 images to highlight what happens after the Tsunami forms.

A) An earthquake results from plate shifting at a subduction zone (oceanic plate being subducted under continental plate). Displaced water forms a tsunami. B) Tsunami separates into two distinct waves – local (to right) and distant (to deep water). C) As local wave encounters continental slope, it gains amplitude (height) and slows down. The trough of the wave, if it encounters the coast first, will cause a drop in water level (drawdown). Note the distant wave traveled much farther from the point of origin since it is moving faster in deep water (adapted from USGS). Note: Wave heights and slopes are exaggerated in comparison to water depths.

If you have questions about the earthquake information or Tsunamis please let us know by leaving your question in the comments section of the blog.

Overall our weather looks very quiet heading into the start of March.  The models have been underdoing temperatures to the tune of about 2-4 degrees each day for Milwaukee.  To me that means we should be in the mid 30s to low 40s over the next week.  The 40s will probably hold off until Thursday at the earliest.  It is safe to say that our snowpack will take a hit over the next week.

Make sure to check back to the blog on Sunday, Mark will have an update on the weather conditions we are expecting and possibly touch on the wet storm that looms for the 7-9 timeframe.  If you are wondering…this is a storm that was highlighted in the long range March forecast in the blog entry below.  Check it out!

Have a great weekend!

Jeremy Nelson


2 Responses

  1. how does a tsuami form??????????

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