<p>Lecture Notes – Chapter 8 • What Are Earthquakes?</p><p>• When the ______, the ______along the edge experience immense ______</p><p>• Eventually the stress becomes too great and ______.</p><p>• Earthquakes are vibrations (in the ______) that result from the ______of</p><p> tectonic (______) plates.</p><p>• An “after shock” ______(that comes after a main event)</p><p>What appears to be the relationship between plate boundaries and Earthquake frequency? </p><p>______</p><p>Cause of Earthquakes - ______Hypothesis</p><p> when rocks are deformed – they ______, releasing stored energy.</p><p>Aftershocks and Foreshocks</p><p>An aftershock - earthquake that follows main earthquake (______). </p><p>A foreshock - earthquake that ______(sometimes).</p><p>Earthquake Storms – ______of ______earthquakes</p><p>8.2 Measuring Earthquakes - Earthquake Waves</p><p>Seismographs (Seismometers) ______earthquake waves.</p><p>Seismograms ______amplified, electronically ______</p><p> records ______/seismometers.</p><p>Types of Waves – Body waves</p><p>P-waves: ______waves PRESSURE WAVES</p><p>– LONGITUDINAL waves (______& stretch Earth’s crust) </p><p>– ______through rock than other seismic waves</p><p>– Travel through solids, ______</p><p>S-waves: ______waves SHEAR WAVES</p><p>– TRANSVERSE waves; ______through rock</p><p>– More ______(horizontal feel)</p><p>Travel ______</p><p>Surface waves </p><p>– only move across the Earth’s surface </p><p>– ______of Earth moving ______</p><p>– Cause the ______due to ______wavelengths Measuring Earthquakes to describe the ______</p><p>—intensity and ______.</p><p>– Richter Scale - Based on ______of the largest seismic wave</p><p>– Each unit = a ______energy increase (______size)</p><p>– Does ______estimate size of ______earthquakes well</p><p>– How many earthquakes each year are about the size of the Haiti Earthquake? _____</p><p>– Momentum Magnitude - amount of displacement along the fault zone </p><p>– ______- most widely used because it estimates </p><p>______released. Measures ______earthquakes</p><p>– List one of the large earthquakes, size and comments ______</p><p>– Mercalli Scale Based on an Earthquakes ______. ______scale</p><p>– ______Scale. What’s the strongest earthquake on Mercalli Scale? ______</p><p>Triangulation and Earthquakes</p><p>• Each station measures ______using the ______</p><p>• ______wave arrival times.</p><p>Triangulation Questions/Graph</p><p>1. What is on the y-axis? ______</p><p>2. What is the red squiggly line called? A s______</p><p>3. What is the difference in arrival times between the p and s waves? ______minutes.</p><p>4. How far away was the earthquake from the unknown seismograph station? ____ Estimate location.</p><p>Triangulation Earth Picture</p><p>1. How far away was the earthquake from Paris? ______km.</p><p>2. What ocean was the earthquake located in? ______. What kind of boundary is this? ______</p>