Chapter_7 - 7 Earthquakes and Related Phenomenon The 1994...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Earthquakes and Related Phenomenon 7
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The 1994 Northridge earthquake on January 17, 1994 killed 57 people and caused $40 billion in damages lasted for 15 seconds Several structures were damaged The rupture of rocks that caused this earthquake was at 18km depth The rupture progressed 20km in a westward direction The events resulted in uplift and folding of Santa Susana mountains
Background image of page 2
Earthquake magnitude >8 Great earthquake 7-8 Major earthquake 1 unit change = 30 times more energy
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Earthquakes • 1 million earthquakes occur every year • Not many (or any) of them are of the magnitude and destruction of the 1994 Northridge earthquake • Earthquakes can be compared to each other by their magnitude or intensity of shaking • Table 5.1 lists the major earthquakes that have affected United States
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Definitions • The place earthquake starts is called epicenter • Epicenter is the location on the surface of the earth above the focus which is the point in the earth where the rocks rupture • Energy released by the earthquake is termed as moment magnitude • Moment magnitude accounts for the physical characteristics of the earthquake, area ruptured on the fault plane, amount of movement/fault slip and rigidity of the rocks
Background image of page 6
Definitions (contd.) • Richter magnitude (old definition) was used to describe the energy of the earthquake • Richter magnitude is based on the largest seismic wave produced by the earthquake. • Seismograph is an instrument that records earthquake displacements; the amplitudes are converted into magnitudes • Ritcher scale 7 produces a displacement 10 times that of magnitude 6.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Earthquake catastrophes are devastating events that take thousands Of lives in matter of seconds. Some of the worst earthquakes are 16 th century China 850,000 lives 1923 Tokyo 143,000 1985 Mexico City 10,000 1995 Kobe 5,000 2001 Gujarat 30,000
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
• Modified Mercalli Intensity Scale, Table 5.4 • Qualitative description of effects • Figure 5.5 shows spatial variation of the intensity for the 1971 San Fernando earthquake (M 6.6) • Data is recorded from a high density seismic network to form such a map. • Such maps allow emergency response.
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 68

Chapter_7 - 7 Earthquakes and Related Phenomenon The 1994...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online