1. GLG 101 - Physical Geology Bob Leighty Earthquakes

2. These lecture notes are very similar to the ones I use in my traditional classes. You’ll find they are loaded with imagery and streamlined text that highlight the most essential terms and concepts. The notes provide a framework for learning and, by themselves, are not meant to be a comprehensive source of information. To take advantage of the global knowledge base known as the Internet, I have included numerous hyperlinks to external web sites (like the Wikipedia, USGS, NASA, etc.). Follow the links and scan them for relevant info. The information from linked web sites is meant to supplement and reinforce the lecture notes – you won’t be responsible for knowing everything contained in them. As a distance learning student, you need to explore and understand the content more independently than in a traditional class. As always, I will help guide you through this learning adventure. Remember, email Dr. Bob if you have any questions about today’s lecture (rleighty@mail.mc.maricopa.edu).rleighty@mail.mc.maricopa.edu Leave no questions behind! Explore and have fun! These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook.

3. What’s Shakin’? Earthquakes  National Earthquake Information Center (NEIC)NEIC World seismicity 1990-2000

4.  Destructive (in lives & property) Mexico City (1985) Earthquakes: why do we care? Earthquakes

5.  Some types of building sites are better than others Earthquakes: why do we care? Earthquakes > Bedrock is better than soft sediment

6.  We can learn about the Earth's interior & tectonic platestectonic plates Earthquakes: why do we care? Earthquakes

7.  Elastic rebound theory - Stress builds up until rocks deform elastically and then break, releasing energy Elastic rebound theory  The size of a quake  the amount of built-up stress What is an earthquake? Earthquakes  Quake = A sudden release of stored energy causing vibrations (seismic waves) in rock Quake

8.  Mostly occur at plate boundaries (~95%)  Originate within the brittle part of the lithospherelithosphere Where do earthquakes occur? Earthquakes

9.  Focus - The actual location within the Earth where the earthquake originates  Epicenter - The point on the Earth's surface above the focus Epicenter Where do earthquakes occur? Earthquakes

10.  Fastest (4 to 7 km/sec)  Can move through solids & liquids P-waves Seismic Waves Earthquakes Body Waves  P-wave = primary wave or compressional wave P-wave

11.  Slower (2 to 5 km/sec)  Can move only through solids S-waves Seismic Waves Earthquakes Body Waves  S-wave = secondary wave or shear wave S-wave

12.  Seismometer - Detects and records vibrations (earthquakes, nuclear blasts, etc.) Seismometer Locating Earthquakes Earthquakes

13.  Seismogram - Record of vibrations (paper, electronic) Seismogram Locating Earthquakes Earthquakes

14. P S surface lag time Locating Earthquakes Earthquakes

15.  To get the distance to an earthquake epicenter, we need: 1) the difference in arrival times (lag time) between P & S waves 2) data from 3 different seismic stations Locating Earthquakes Earthquakes

16. Magnitude  Richter Scale = measures earthquake intensity (energy) from ground shaking Richter Scale  Determined by measuring amplitude (height) of the S-wave on seismogram  Richter scale is logarithmic (each interval x10) Earthquake Intensity Earthquakes  Seismic Moment Scale - A better estimate of earthquake energy, now the standard Seismic Moment Scale

17.  Duration of earthquake  Population density  Distance from focus / depth of earthquake  Soft sediment vs. dense bedrock Controls on Earthquake Damage Earthquakes  Building design and construction

18. Ground Rupture Destructive Effects Earthquakes

19. Ground Rupture Destructive Effects Earthquakes

20.  Liquifaction - Soft sediment can amplify vibrations (water- saturated sediment can liquefy & turn to goop) LiquifactionLiquefaction Destructive Effects Earthquakes

21.  Broken gas lines, water pipes, etc. ex - San Francisco, CA (1906): 90% of EQ damage caused by fire ex - Yokohama, Japan (1923): 576,262 houses burned, 143,000 people killedFire Destructive Effects Earthquakes

22.  Tsunami - Caused by the sudden displacement of water Tsunami  NOT a tidal wave Tsunami Destructive Effects Earthquakes

23.  Fast, but low in open ocean  Big & bad near shore (average up to 30 m high) Tsunami Destructive Effects Earthquakes

24. Tsunami Earthquakes

25. http://serc.carleton.edu/NAGTWorkshops/visualization/collections/tsunami.html http://www.ess.washington.edu/tsunami/index.html http://www.volcanolive.com/tsunami10.htmlTsunami Destructive Effects Earthquakes

26. Tsunami Earthquakes

27. WWW Links in this Lecture > NEIC - http://earthquake.usgs.gov/regional/neic/http://earthquake.usgs.gov/regional/neic/ > Tectonic plates - http://en.wikipedia.org/wiki/Tectonic_plateshttp://en.wikipedia.org/wiki/Tectonic_plates > Elastic Rebound Theory - http://en.wikipedia.org/wiki/Elastic_rebound_theoryhttp://en.wikipedia.org/wiki/Elastic_rebound_theory > Earthquake - http://en.wikipedia.org/wiki/Earthquakehttp://en.wikipedia.org/wiki/Earthquake > Lithosphere - http://en.wikipedia.org/wiki/Lithospherehttp://en.wikipedia.org/wiki/Lithosphere > Epicenter - http://en.wikipedia.org/wiki/Epicenterhttp://en.wikipedia.org/wiki/Epicenter > Seismic waves - http://en.wikipedia.org/wiki/Seismic_wavehttp://en.wikipedia.org/wiki/Seismic_wave > P-wave - http://en.wikipedia.org/wiki/P_wavehttp://en.wikipedia.org/wiki/P_wave > S-wave - http://en.wikipedia.org/wiki/S_wavehttp://en.wikipedia.org/wiki/S_wave > Seismometer - http://en.wikipedia.org/wiki/Seismometerhttp://en.wikipedia.org/wiki/Seismometer > Seismogram - http://en.wikipedia.org/wiki/Seismogramhttp://en.wikipedia.org/wiki/Seismogram > Richter Scale - http://en.wikipedia.org/wiki/Richter_magnitude_scalehttp://en.wikipedia.org/wiki/Richter_magnitude_scale > Liquifaction - http://en.wikipedia.org/wiki/Earthquake_liquefactionhttp://en.wikipedia.org/wiki/Earthquake_liquefaction > Tsunami - http://en.wikipedia.org/wiki/Tsunamihttp://en.wikipedia.org/wiki/Tsunami > http://www.ess.washington.edu/tsunami/index.htmlhttp://www.ess.washington.edu/tsunami/index.html > http://www.volcanolive.com/tsunami10.htmlhttp://www.volcanolive.com/tsunami10.html > http://serc.carleton.edu/NAGTWorkshops/visualization/collections/tsunami.htmlhttp://serc.carleton.edu/NAGTWorkshops/visualization/collections/tsunami.htmlEarthquakes