Section 2-2 Measuring Earthquakes Erick A. Fernandez Austin donckels Miraj S Porter 12-10-07

Focus Point beneath Earth’s surface.

Seismic Wave A vibration.

Epicenter The surface above the focus. A seismic wave is a vibration through Earth releasing energy

Primary Wave A p-wave compresses and expands. Ex: like an accordion.

Secondary Wave Is a vibration from side to side or up and down.

Surface Wave It moves slower than a p-wave and an s-wave.

Mercalli Scale The Mercalli Scale rates Earthquakes.

Seismograph A Seismograph records the ground movement.

Magnitude Measures the ground earthquake.

Richer scale Measures the size of a seismic wave.

Moment Magnitude Scale A Moment Magnitude Scale releases energy.

Seismic Waves During an earthquake,seismic waves races out from the focus in all directions. Seismic waves travel like ripples in a pond, they carry the energy of an earthquake away from the focus through, the Earth’s interior and across the surface. The energy of the seismic wave is greater at the epicenter. There are four categories of seismic waves: P waves, S waves, and surface waves. The first waves to arrive are P-waves and S-waves.

Detecting Seismic Waves Geologist use instruments called seismographs. A seismograph records the ground movement caused by seismic waves that move through earth. recently scientists used mechanical seismograph. It consists of a heavy weight attached to a frame by a spring or wire. A pen connected to the weight rest,it’s point on a rotating drum.When the drum is still the pen draws a straight line on the paper wrapped around the drum. During a earthquake seismic waves cause the drum to vibrate.

Detecting Seismic Waves (continued) The higher lines on the drum mean the earthquake is bigger.

Measuring earthquakes Magnitude is a measurement of earthquake strength based on seismic wave and movement along the fault. The Mercalli scale is not a precise measurement. The richer scale was developed in the 1930s. The moment magnitude can be used to rate an earthquake of all near and far. To rate on earthquakes on the moment magnitude scale,geologist first study data from modern electronic seismograph.

Locating the Epicenter Geologists use seismic waves to locate the earthquake’s epicenter. Seismic waves travel fast. P-waves are the first to arrive at a seismograph. S-wave’s come close behind. To tell how far the seismograph is from the epicenter, scientist’s measure the difference between the arrival time of P-wave’s and S-wave’s. Geologists draw three circles using data from the seismograph’s station’s all over the world.

What we learned We learned that the Richter scale was developed in the 1930s. Also seismic waves carry the energy of an earthquake away from the focus to the epicenter,to the seismograph.

Grade Rubric for Erick A. Fernandez Presentation has title, mentions member’s names, and includes a complete date. Topic slides are well thought out, informative, full of details, and demonstrate a deep understanding of the subject. Presentation is very creative, animated, and uses many of the formatting techniques learned in class. Student helped gather the information, cooperated with the formatting, and helped the group stay focused by avoiding off-task behavior. TOTAL: 3 3 20 20 10 10 7 7 40 40 Science

Grade Rubric for Austin Donckels Presentation has title, mentions member’s names, and includes a complete date. Topic slides are well thought out, informative, full of details, and demonstrate a deep understanding of the subject. Presentation is very creative, animated, and uses many of the formatting techniques learned in class. Student helped gather the information, cooperated with the formatting, and helped the group stay focused by avoiding off-task behavior. TOTAL: 3 3 20 20 10 10 7 7 40 40 Science

Grade Rubric for Miraj Porter Presentation has title, mentions member’s names, and includes a complete date. Topic slides are well thought out, informative, full of details, and demonstrate a deep understanding of the subject. Presentation is very creative, animated, and uses many of the formatting techniques learned in class. Student helped gather the information, cooperated with the formatting, and helped the group stay focused by avoiding off-task behavior. TOTAL: 3 3 20 20 10 10 7 5 40 38 Science

Teacher Notes Excellent use of pictures to describe your vocabulary Great summaries of main ideas “What we Learned” section needed more thought and details Nice job with the formatting of the presentation Science