Mountain Building and Earthquakes Current Weather Faulting Mountain

Mountain Building and Earthquakes • • • Current Weather Faulting Mountain Building Earthquakes Tsunami Disasters For Next Class: Read rest of Chapter 12

Plate Boundaries, Earthquakes, and Volcanoes Figure 11. 27

Types of Faults: Normal Fault Figure 12. 12 a

Types of Faults: Reverse Fault Figure 12. 12 b

Types of Faults: Transform Fault Figure 12. 12 c

The San Andreas Fault Figure 12. 14

Orogenesis • What does orogeny mean and what are three types of orogenesis?

Orogenesis (Mountain Building) • Orogeny means “mountain generating. ” • Types of orogenesis – Oceanic plate–continental plate collision orogenesis – Oceanic plate–oceanic plate collision orogenesis – Continental plate–continental plate collision orogenesis

Major Orogenies Figure GIA 12. 1

Mountain Building: Oceanic–Continental Figure GIA 12. 2 a

Mountain Building: Oceanic–Oceanic Figure GIA 12. 2 b

Mountain Building: Continental–Continental Figure GIA 12. 2 c

Folded Appalachian Mountains Figure 12. 16

Introduction to Earthquakes • There approximately one million earthquakes every year that can be felt by people somewhere on Earth. • Energy released from an earthquake is called the magnitude of the earthquake. • The intensity of shaking is referred to as ground motion.

Focus, Epicenter, Foreshock, and Aftershock • A focus of an earthquake is the subsurface area along a fault plane, where the motion of seismic waves is initiated. • An epicenter is the area at the surface directly above the focus. • An aftershock or a series of aftershocks may occur after the main shock. • A foreshock is also possible, preceding the main shock.

Elastic Rebound Theory Figure 12. 17

Earthquake Anatomy Figure 12. 18

Seismic Waves and Seismograph Figure 12. 19

Earthquake Scales • Modified Mercalli scale – Measures intensity of shaking and damage • Richter scale – Measures amplitude of seismic waves • Moment magnitude scale – Measures energy released

Intensity and Ground Shaking

Earthquake Magnitude • Quantitative magnitude-of-energy-released scale • Richter scale is based on amplitude of seismic waves. – Related to energy released • Moment magnitude scale is based on – Amount of fault slippage produced – Size of surface area that ruptured – Nature of the materials that faulted • More accurate than Richter scale for very large earthquakes

Loma Prieta Earthquake and Ground Shaking Figure 12. 20

2004 Indian Ocean Tsunami Disaster • https: //www. youtube. com/watch? v=j 9 JDz. B Twiig

2011 Japan Earthquake and Tsunami Figure 12. 21

2011 Japan Earthquake and Tsunami • https: //www. youtube. com/watch? v=o. Wzdg BNfh. QU

1970 Peru Earthquake • https: //www. youtube. com/watch? v=Tzt 12 J p. Ce 9 o

Earthquake Hazard Map Figure 12. 23

Earthquake Forecasting • Long-term forecasts (10 to a few thousand years) • Medium-range predictions (a few years to a few months) • Short-range predictions (a few days or hours)

Earthquake Planning • Development of hazard-reduction programs • Careful sitting of critical facilities • Engineering and land-use adjustments to earthquake activity • Development of a warning system