San Francisco 1989: Fire erupts in the hard-hit "Marina District" of the city.

What is an Earthquake? Natural rapid shaking of LITHOSPHERE (CRUST) LITHOSPHERE (CRUST) ENERGY Releases ENERGY stored in rocks

What Happens to Rock? RAISED UP -Uplifted– RAISED UP Ex: Fossil 100 meters ABOVE ABOVE sea level - MOST sedimentary rocks show ORIGINAL HORIZONTALITY DEFORMED LAYERS CRACK -Faulted -displaced along a CRACK BENT or CURVED -Folded- BENT or CURVED

Where do Earthquakes START? FOCUS - Start at one particular point called FOCUS FOCUS BENEATH –Point BENEATH earth’s surface where rock breaks under stress ON -Point ON surface directly above focus is called EPICENTER

Measuring Earthquakes SEISMOGRAPH - Instruments used to measure earthquake called SEISMOGRAPH The needle records motion of the earth, it leaves a wavy line.

Seismogram SEISMOGRAMThe recording is called a SEISMOGRAM

Measuring Earthquakes SEISMIC WAVES -Energy of quake is carried through SEISMIC WAVES 3 TYPES: 1) P waves 2) S waves 3) SURFACE WAVES

P waves SOLIDS LIQUIDS - Move through SOLIDS & LIQUIDS PHURST - PHURST to arrive at epicenter PRIMARY - PRIMARY WAVES SAME - Vibrate in the SAME direction the waves are moving

S waves SOLIDS -Move ONLY through SOLIDS SECOND -SECOND to arrive at epicenter SECONDARY WAVES -SECONDARY WAVES RIGHT ANGLES - Vibrate at RIGHT ANGLES to the direction the waves are moving

Detecting & Measuring Seismic Waves -3 rating scales to measure earthquakes: Mercalli scale 1) Mercalli scale Richter scale 2) Richter scale Moment magnitude scale 3) Moment magnitude scale

Mercalli Scale

Richter Scale

Moment magnitude scale OFTEN Most OFTEN used to measure strength of earthquake Use HEIGHT Use HEIGHT of wiggles on seismograms to infer total amount of energy

Earthquake SAFETY? 3) Proper PLANNING & CONSTRUCTION of building 1) DROP, COVER, HOLD 2) Earthquake DRILLS

Tsunami LARGE UNDERWATER LARGE UNDERWATER earthquake FAULTING Caused by FAULTING associated with an earthquake

DAMAGE of INDONESIA TSUNAMI

Height of Tsunami Waves

How would a map showing the location of active volcanoes compare to the map showing the location of earthquake epicenter? ANS: (2) 1)Small percentage of volcano locations would be in the same regions as the epicenter 2) Large percentage of volcano locations would be in the same regions as the epicenter 3)There would be no match between the locations of the volcanoes and the epicenters 4)The location of the volcanoes and the epicenters would only match in the ocean regions

Earthquakes generate P-waves and S-waves. Compared to the speed of the S-waves in a given Earth ’ s material, the speed of the P-waves is 1) always slower 2) always faster 3) always the same 4) sometimes faster & sometimes slower ANS: (2)