1. Earthquake Magnitudea. The epicenter of the earthquake is the location on the surface of the Earth above the focus, which is the point where the rocks ruptured to produce the earthquake.b. Moment magnitude- the measure of the energy released by the earthquakei. Based on physical characteristicsc. Richter magnitude – used to describe the energy released by an earthquakei. Based on amplitude, size, or the largest seismic wave produced during an earthquakeii. Seismographs measure this on a scale of 101. A magnitude 7.0 earthquake is 10x bigger than a 6.02. Earthquake Intensitya. Intensity reflects how people perceived the shaking, and how structures responded to the shakingb. Earthquakes have one magnitude but can have multiple intensitiesc. Measured by the qualitative, Modified Mercalli Scale3. Different kinds of Earthquakesa. Interplate – Occur between two plates (ex: Pacific&North America)b. Intraplate – Occur within a single plate boundary4. Earthquake Processesa. Faultingi. Lithospheric plates slide past eachother.ii. Rocks along the boundary undergo strain or deformations, resulting from stress.iii. When stress exceeds their strength, the rocks rupture forming a fault and producing an earthquake.5. Earthquake Shakinga. Three factors determine shaking felti. Earthquake magnitudeii. Distance from the epicenteriii. Local soil and rock conditionsb. Types of Seismic Wavesi. P waves (compressional) – faster, can travel through solid, liquid and gaseous materialsii. S waves (shear) – can only travel through solid materialsiii. R waves (surface) – when seismic waves reach surface they are called surface waves.6. Earthquake Cyclea. Hypothesis proposes that there is a drop in elastic strain after an earthquake and a reaccumulation strain before the next event.b. Stages of Earthquake Cyclei. Long period of seismic inactivity following a major earthquake and associated aftershocksii. Increased seismicity, as accumulated elastic strain approaches and locally exceeds the strength of the rock. Produces small earthquakes.iii. Foreshocks are small to moderate earthquakes that occur before the big oneiv. The major earthquake is the final stage7. Effects of Earthquakesa. Shaking and Ground Rupturei. Could create Fault Scarpsb. Liquefactioni. Transformation of water-saturated granular material, or sediments, from a solid to a liquid state.ii. Building may tilt or sink into the liquefied sedimentsiii. Tanks or pipelines buried in the ground may rise buoyantlyc. Landslidesd. Firesi. Shaking can break electrical power and gas linese. Diseasei. Northridge earthquake raised large volumes of dust, some of which contained fungi spores that caused valley feverii. Earthquakes can also rupture sewer and water lines causing water to become polluted by disease causing organisms.f. Regional Changes in Land Elevationi. Can lead to flooding8. Tsunamia. Produced by the sudden vertical displacement of waterb. Caused by:i. Earthquakesii. Underwater landslidesiii. Collapse of part of a volcanoiv. Submarine volcano explosion9. Response to Earthquake Hazardsa. Make adjustments for potential earthquake activityb. Install earthquake warning systemsc. Educate people on the dangers of earthquakesd. Instruct everyone to turn off the gas10. P waves will comes first and can be heard, but the S and R waves will arrive later and cause most of the damageChapter 6 Notes 09/19/20101. Earthquake Magnitudea. The epicenter of the earthquake is the location on the surface of theEarth above the focus, which is the point where the rocks ruptured to produce the earthquake.b. Moment magnitude- the measure of the energy released by the earthquakei. Based on physical characteristicsc. Richter magnitude – used to describe the energy released by an earthquakei. Based on amplitude, size, or the largest seismic wave producedduring an earthquakeii. Seismographs measure this on a scale of 101. A magnitude 7.0 earthquake is 10x bigger than a 6.02. Earthquake Intensitya. Intensity reflects how people perceived the shaking, and how structures responded to the shakingb. Earthquakes have one magnitude but can have multiple intensitiesc. Measured by the qualitative, Modified Mercalli Scale3. Different kinds of Earthquakesa. Interplate – Occur between two plates (ex: Pacific&North America)b. Intraplate – Occur within a single plate boundary4. Earthquake Processesa. Faultingi. Lithospheric plates slide past eachother.ii. Rocks along the boundary undergo strain or deformations, resulting from stress. iii. When stress exceeds their strength, the rocks rupture forming afault and producing an earthquake.5. Earthquake Shakinga. Three factors determine shaking felti. Earthquake magnitudeii. Distance from the epicenteriii. Local soil and rock conditionsb. Types of Seismic Wavesi. P waves (compressional) – faster, can travel through solid, liquid and gaseous materialsii. S waves (shear) – can only travel through solid materialsiii. R waves (surface) – when seismic waves reach surface they arecalled surface waves.6. Earthquake Cyclea. Hypothesis proposes that there is a drop in elastic strain after an earthquake and a reaccumulation strain before the next event.b. Stages of Earthquake Cyclei. Long period of seismic inactivity following a major earthquake and associated aftershocksii. Increased seismicity, as accumulated elastic strain approaches and locally exceeds the strength of the rock. Produces small earthquakes.iii. Foreshocks are small to moderate earthquakes that occur before the big oneiv. The major earthquake is the final stage7. Effects of Earthquakesa. Shaking and Ground Rupturei. Could create Fault Scarpsb. Liquefactioni. Transformation of water-saturated granular material, or sediments, from a solid to a liquid state.ii. Building may tilt or sink into the liquefied sedimentsiii. Tanks or pipelines buried in the ground may rise buoyantlyc. Landslidesd. Firesi. Shaking can break electrical power and gas linese. Diseasei. Northridge earthquake raised large volumes of dust, some of which contained fungi spores that caused valley feverii. Earthquakes can also rupture sewer and water lines causing water to become polluted by disease causing organisms.f. Regional Changes in Land Elevationi. Can lead to flooding8. Tsunamia. Produced by the sudden vertical displacement of waterb. Caused by:i. Earthquakesii. Underwater landslidesiii. Collapse of part of a volcanoiv. Submarine volcano explosion9. Response to Earthquake Hazardsa.