Monday, March 24, 2008
During an earth the Richter scale measures how powerful the earthquake is. It measures the energy released during an earthquake. Charles Richter invented it in 1935. The mercali scale measures the intensity of an earthquake. That means it measures how much damage is caused during and after an earthquake to a city. Guiseppe Mercali invented it in 1902. One difference between the two scales is how big each scale is. The Richter scale has ten levels of measuring the energy released from an earthquake, and the mercali scale has twelve levels of measurement that describes the intensity of an earthquake. That’s a main difference between the two scales.
Another main difference between the two scales is the way they measure energy or intensity. The Richter scale is used during an earthquake. Richter scales are used with seismograms to calculate the energy levels of and earthquake. A mercali scale is calculated by a person to decide how much damage was put upon a civilization. The higher the intensity of an earthquake the more damaged a city is. The higher the reading on a Richter the more powerful an earthquake will be.
Another difference between the two scales is the way they calculate energy or intensity. On a Richter scale each level is one hundred times more powful than the last level. So a level two earthquake is one hundred times more powerful than a level one. The intensity of and earthquake is calculated by the damage on a surface to a city. There might be mudslides or fires so the intensity would be at high levels. That’s the difference between the two scales.
Those are some differences between the Richter scale and the modified Mercali scale. They are both very useful to scientists to understand how powerful earthquakes can be. And hopefully scientists will one day be able to predict earthquakes for the safety of people.
Sunday, March 23, 2008
Tokyo, Japan is a society living on an active plate boundary. There are many precautions these people take to handle the effects of volcanoes and earthquakes, many of which will be explained in the following essay.
To reduce damage the buildings have earthquake resistant structures. One part of the structure is base isolation. The building is resting on rollers, so when the ground shakes the rollers move, not the building. Another way of minimizing seismic damage is using Seismic Dampers that act like a car’s shock absorber. The movement may be very large but the dampers absorb part of the energy. A structure may also include ductile materials, like steel, which can tolerate a good amount of inelastic deformation. Of course many things are done that do not have to deal with the building structure, but what the people in the society do for their selves. All the houses are set to standards set by the government, so they are all recognized as safe. Furniture is secured to the walls or ceiling so that nothing collapses during activity, also heavy or large items are to be taken out of top cupboards and shelves moved to bottom ones, where they are less likely to be harmful during tectonic activity. Knowing how and when to shut off the gas of a home is another very important thing the people have learned to handle the dangers. Everyone should know all the exits and keep them clear. One of the most important things these people do is keep a bag for emergencies filled with, food, water, money, flashlights, batteries, radio, and more.
The people of Tokyo, Japan have learned to handle the effects of living on an active plate boundary with ease. Volcanoes and earthquakes are part of their lives and they know how to deal with it. They have many precautions making it easier to deal with. (ME4)
Saturday, March 22, 2008
The Earth was composed of several giant plates, called the Tectonic Plates. On the plates are the continents and the oceans of Earth. The continents were said to have been one big, single, continent called Pangea. Since then, the single continent drifted apart from eachother. About 200 million years ago a sea stretched along the latitudinal area, which today is occupied by the Himalayans. The sea was called The Tethys. The Northern Eurasian land mass and the Southern Indian land mass started depositing large amounts of sediments. The sediments started pouring into the shallow part of the Tethys. The two land masses began colliding with eachother. This phase kept happening over and over. The last major phase happened about 600,000 years ago. These series of phases is what led to the formation of the Himalayas.
Overall, the forces of the Himalayan mountain range was the collision. Also, the deposits from the land masses that filled the sea.
The collison of India and Asia, happened along the convergent boundary.
Today there is still movement in the tectonic plates, due to earthquakes. The Himalayas still rise about 5mm per year. The Himalayas are young, folded mountains.
In conclusion, the theory of the Himalayas in 1912 is the accepted theory, called the Continenal Drift. 200 million years ago is when the two large land masses collided and started forming. Today this is still the accepted theory about the Himalayan mountain range. The Himalayan mountains took a very long time to form. But the forces and time it took to form the mountains, gave us huge and beautiful mountains today.
5:12AM April 18, 1906, San Francisco was struck by one of the highest ranking earthquakes of all time. The massive earthquake ruptured the north most 299 miles of the San Andreas Fault, and destroying over 490 city blocks. Killing about 3,000 people and injuring about 225,000 more. The property damage was a bout 400,000,000 in 1906 money. Most of the destruction occurred from the fires that were ignited from the earthquake. The epicenter was about 2 miles offshore from Mussel Rock, California. The shaking started and lasted about 40-45 seconds long. The earthquake was felt from southern Oregon to south of Los Angeles and as inland as centeral Nevada.
People can educate themselves about earthquakes so they can be familiar with them if they were to happen. Such as learning about aftershocks, this is an earthquake of similar or lesser intensity that follows the main earthquake. It is smart to have a family plan if an earthquake were to happen. Some things in that plan may be knowing the safe spot in each room, physically practice safety drills, have a first-aid handy, know CPR, and having a place where you and your family can reunite if separated. You should prepare your house, and what’s in it. A lot of the damage caused by an earthquake is from objects in your house. During the shaking, cabinets and the things that are in it topple, the windows shatter, and hanging plants and light fixtures fall. You can reduce the risk of injuries and damage to your house by removing, moving, fastening or simply latching the items that are more likely to fall over and seriously injure someone to something that can withstand all of the shaking of an earthquake.
Some safety measures you can take when an earthquake actually occurs are minimizing your movements; only take a couple small steps to a close by place that may be safer. Try not to panic, instead steady yourself and try to think clearly. When you feel an earthquake happening (shaking of the ground), you should duck under a sturdy table or desk. Don’t move or let go of that object until the shaking stops. Stay as far away from bookcases, windows, heavy mirrors, file cabinets, hanging plants, hanging light fixtures, or any other heavy objects that could harm you.
Those are the most important things you should do to prepare your house and yourself if an earthquake were to occur. Even though earthquakes can be extremely dangerous, the precautions and safety measures you can take may someday save your life.