<p> HOTSPOTS</p><p> Areas of unusually high volcanic activity </p><p> Unusually hot magma rises in the mantle & breaks through the crust, forming a volcano</p><p> The Hawaiian Islands were formed by a hot spot </p><p> As the Pacific Plate moves northwest, the hot spot stays in place, making a chain of volcanoes</p><p>EARTHQUAKES</p><p> Earthquakes occur whenever there is movement of Earth’s Tectonic Plates.</p><p> They occur along all types of plate boundaries and along faults within the plates</p><p>Structure of an Earthquake</p><p>1* The FOCUS is the point underground where the earthquake originated</p><p>2* The EPICENTER is the point on the surface directly above the focus.</p><p>Types of Seismic Waves</p><p>3* P: “Primary” or “Push-Pull” waves, first to arrive (fastest waves), causes ground compression and expansion</p><p>4* S: “Secondary” or “Shear” waves, travel half the speed of P waves, moves ground side-to-side and up-and-down</p><p>5* SURFACE WAVES; Arrive last, travel the slowest, but cause the most ground movement and damage Locating the Epicenter of an Earthquake</p><p>6* The device that detects seismic activity is called a SEISMIGRAPH</p><p>7* The paper that records the seismic activity is a SEISMIGRAM</p><p>8* In order to locate the Epicenter, you must have data from 3 seismic stations.</p><p>Measuring Earthquakes</p><p>9* Earthquake intensity is measured using the RICHTER Scale</p><p>10* Each number on the scale releases about 31 times* more energy than the previous number * So, an 8.0 earthquake releases 29,791 times more energy than a 5.0</p><p>Effects of an Earthquake</p><p> Collapsed buildings & bridges</p><p> FIRES (from broken gas lines)</p><p> LANDSLIDES & LIQUEFACTION</p><p> TSUNAMIS</p><p>Studying Earth’s Interior</p><p> We know the structure of Earth’s interior from studying the P & S WAVES of earthquakes</p><p> P-WAVES can travel through any material, but they bend when moving through liquid. This bending creates “SHAWDOW ZONE”</p><p> S-WAVES can only travel through solids, so they create a much larger “shadow zone” on the other side of the Earth. </p>