Measuring and Locating the Epicenter of Earthquakes


Earthquakes are measured using intensity and magnitude scales. The Mercalli scale measures the intensity of an earthquake based on the reports of people who experienced or observed the amount of destruction it caused. The most dependable measurements of earthquakes, however, are made with seismographs. Seismographic records of earthquakes have established magnitude scales. The Richter scale is one such magnitude scale.

A seismograph records the magnitude of an earthquake and the time the seismic waves arrive. Seismologists use the difference in the speeds of P- and S-waves to locate the epicenter of earthquakes.

Assignments:

the Volcano Reports are due Monday, April 20, 2009.

Homework # 10: Due Thursday, April 23, 2009

In Review Book, read pages 54-58. Do questions 1-16

Welcome back! I hope everyone had a great spring break.

Comments

Anonymous said…
Mr. Longoria, my printer isnt working at all i was wonderng if it was possible 2 email the project to you
April 19, 2009 at 11:04 AM
Mr. Longoria said…
Yes. However, if it is submitted after April 20, it will be marked late.
April 22, 2009 at 6:21 AM
Post a Comment

Popular posts from this blog

Rock Cycle

Image
The rock cycle is a model of the natural changes that occur in rocks and rock materials on the earth. The diagram to the right distinguishes between those processes that take primarily at Earth's (external processes) and those that take place within the Earth (internal processes).  Internal processes, such as compression and heating require the conditions of extreme temperature and pressure that occur deep within the Earth. The rock cycle illustrates several important principals of geology. First, nearly all rocks are made from the remains of other rocks (coal and other organic sedimentary rocks are important exceptions).  Second, rocks are classified on the basis of their origin.  Finally, there are a variety of ways that rocks can change in response to changing conditions at the surface or within Earth. Homework  due Wednesday, April 6, 2011 Review Book:  read pages 55-56; do questions 54-60 on pages 56-57, and questions 1-10 on pages 59-60.
Read more

Phases of the Moon

Image
As moon orbits Earth, the Sun always illuminates one-half of the moon surface.  Viewed from Earth, the moon's phases are seen as different portions of the illuminated sphere. No other object in the night sky is as spectacular as Earth's moon.  For almost all of recorded human history, the moon has inspired myths, songs, poems, and superstitions. Phases of the Moon The moon completes one revolution around the Earth in 27.3 days. During this orbit, the illuminated area of the moon increases and then decreases. This effect makes the moon appear to change shape. These phases (apparent changes in shape) of the moon are caused by the constant changes in relative positions of Earth, the Sun, and the moon.  When the moon and the Sun are on the same side as the Earth, the moon's dark side faces Earth. At this time, the moon's illuminated side is not visible from Earth.  This is the new moon phase.  The above figure illustrates the way light and shadow on the orb...
Read more

Igneous Rock Classification

Image
The most common igneous rocks are classified using just two characteristics: Crystal size and color. For example, basalt is relatively dark in color (gray to black) and usually contains crystals to small to see without the aid of an optical lens.  On the other hand, granites are lighter in color (pink to gray) and have crystals that can be seen by the naked eye.  Igneous rocks are the only kind of rock that forms from hot magma, and all rock that crystallize from melted rock are igneous.  
Read more