SHAKE, RATTLE AND ROLL

       EARTHQUAKES AND SEISMOLOGY

 

          When I was a young boy I awoke to the rattling of an earthquake. It was about 6:30 a.m. in the morning. My dad was just getting ready for work and mom was up preparing breakfast for dad and trying to get things together for the rest of us so that my sister and younger brother and I could attend school. I tried to get out of bed but the bed because of the earthquake was moving around the room. I yelled at mom but she was in the front of the house and could not make it back through the hallway to my bed room. Things were falling on the floor and my heart was beating so fast I could hardly breathe. The more I tried to get out of bed the more I was pushed back by the rumbling of the earthquake and bed. That was the first earthquake I had ever experienced.

         My dad had told us about earthquakes he had felt in his home town of Monroe, Utah when he was a young lad. He said boulders would roll from Monroe Mountain down in to the town when the earthquakes occurred. There were times when I was young that we stayed in Monroe and I was very sensitive about the subject of earthquakes, I was about nine years old at the time.

          One time my dad said he felt and earthquake when he was in bed. When he was a young boy the kids slept out side when the weather was warm enough. His uncle had set up a real bed out side for him and his cousins to sleep in because the house was so small it was better for the whole family. Well during the night the cow had escaped from the corral and was rubbing or itching its self on the other side of the bed the kids were sleeping on. My dad woke up and thought they were having an earthquake he woke his cousin who was staying with them. They both jumped out of bed only to find out it was just the family cow that had frightened them.

           About two weeks after my first earthquake I was standing on a chair trying to get something from atop the refrigerator. All of the sudden the refrigerator was trying to attack me or so I thought. It was moving back and forth  from the earthquake and was about to fall over with me by its side when mom pulled me from the chair and we headed out side just in time to see   three or four waves from the earthquake move from our house east across the street towards our neighbors house. The  earthquake waves were about an inch or so high and moved just like a wave on a lake or pond when you throw a huge rock in the water. When the waves reached the other house you could see the windows rattle. That was a strange feeling to see waves move across solid ground.

          The next time I felt an earthquake was about twenty years later, my brother his wife and I were attending a church meeting when all of the sudden I thought I was having a dizzy spell but then I herd some one say what was that. Just then the chandeliers in the church began to sway. We later found out the epicenter of the earthquake was in Idaho.

          Earthquakes are felt all over the earth but some areas like thering of fire seismic belt that surrounds the Pacific Ocean or the seismic belt that runs from India to the Mediterranean ocean feels earthquakes more often. The earthquakes are usually more severe as well.

          Scientists who study earthquakes andplate tectonics understand why earthquakes are generated and why they are felt in some areas more often than other areas. The earth is kind of like an egg with cracks in the shell running in every direction all over the surface of the egg. All the areas between the cracks are similar to theindividual plates that cover the earth surface. These plates rub and grind against one another generating earthquakes in the process. Today we know they rub past one another in a horizontal fashion like what happens in the state of California along the San Andres fault zone. Or they dive beneath another plate generating volcanoes and earthquakes like what you see in the states of Oregon, Washingtonand Alaskaor in the west pacific like the country of Japan. Not only are earthquakes and volcanoes generated but tsunamis as well and we all know what happened in Indonesia a few years ago. Two hundred thousand or more people were killed in a very short time. A friend of mine experienced the tsunamis while visiting his native county of Thailand. He was caught in the back of a camera shop that was near the sea. He nearly drown and in the process lost many personal possessions including his wallet and all of his money. The state of Hawaii has been the victim of many tsunamis as well.

The above picture is called a slickensides. This polished surface is created when two slabs of rock are ground aginst one and other creating a fault zone in the the rock

The above picture is mount Olympus part of the Wasatch mountain range. The Wasatch fault zone lies to the west of mount Olympus in Salt Lake valley

         In Utah were I live earthquakes are generated when the earth moves up and down in a vertical motion along lines of stress called fault lines. Here one block of earth  (fault block Valley floor) moves downward in relation to the other block(fault block mountains). Stress is built up in the blocks of earth by the movement of the plates that was discussed earlier as the stress builds up and friction can no longer hold the blocks in place finally the blocks move violently past one another creating shock waves that move out from the epicenter of the earthquake to distant areas miles from the center of the earthquake destroying buildings creating landslides and turning old lake beds into a muddy sandy liquid soup this process is called liquefaction in which structures like buildings can no loger be supported by the ground underneath.

        Earthquakes are measured using a system called the Richter scale with one being the smallest and ten being the largest. However if you measured two earthquakes with one being measured at two and the other earthquake measured at three on the Richter scale the three earthquake would be ten times more damaging than the two earthquake.

        P waves are push pull waves and S are shear waves. both are generated during and earthquake event. P waves travel through the earth and S waves travel on through the earth also but travel more slowly. As a result the P waves get to the seismograph faster than the S waves so if you time the two waves you can calculate the distance from the site of the seismograph to the site of the epicenter of the earthquake if you  measure from at least three different locations.

       Earthquakes are measured by instruments called seismographs. Seismographs come in two forms and are ether a vertical seismograph or a horizontal seismograph. Seismographs measure two things the intensity or magnitude of the wave and the duration of the wave.


Above is a picture of the EQ-1 Seismograph manufactured by Steiner Enterprises Inc and distributed
by wards scientific. this one is set up in my basement in my home

EARTHQUAKES HEADLINES

 This is the bad news on May 12th  an 7.9 earthquake struck china. Today may 16th 21,500  are feared dead in china and the figure is likely to climb.
The Sichuan earthquake occurred on may 12th at 06:28:01 UTC time and was recorded at my seismic station in West valley city Utah at 06:41:52  thirteen minutes and 51 seconds later. It was a 7.9 magnitude earthquake that occurred 19 km (11.8) miles below the ground. The seismogram above was recorded at my station in west valley city.

 

Pictures of Wells Nevada Earthquake damage 2008

Wells Nevada earthquake damage to the old business distric from the 6.0 earthquake that struck Wells in Febuary 2008

 

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