Lecture 20 That was the year* that Lisbon town Saw the earth opened up and gulp her down. (*1755) - Oliver Wendell Holmes (The Deacon’s Masterpiece) Earthquakes Webpage for course (dayt ime) Webpage for course (nigh ttime)
Jan 07, 2016
Lecture 20
That was the year* that Lisbon townSaw the earth opened up and gulp her down.
(*1755)
- Oliver Wendell Holmes (The Deacon’s Masterpiece)
Earthquakes
Webpage for course (daytime)
Webpage for course (nighttime)
2nd test scores
125 (2)
123 (2)
122
121
120
118
113
112 (2)
110
109
108
107
106 (2)
103
101
100
95 (2)
93
91
88 (2)
84
82
81
80
74
67
64
Seismology – the study of earthquakes
Seismometer
Seismograph
Seismogram
Fig. 14.7, p. 325
Ripple analogy
Three basic types of waves:
Longitudinal (compressive, Primary, P-wave)
Transverse (shear, secondary, S-wave)
Surface waves
Three basic types of waves:
Longitudinal (compressive, Primary, P-wave)
Sound
Three basic types of waves:
Transverse (shear, secondary, S-wave)
Light, radio, RADAR(electromagnetic waves)
Three basic types of waves:
Surface waves
P- and S-waves:
P-waves travel faster than S-waves
P-waves travel through solids and fluidsS-waves do not travel through fluids
So, three questions:
How do you tell how far away a quake is?How do you tell where a quake is?How do we know the earth’s core is molten?
How do you tell how far away a quake is?
How do you tell where a quake is?
How do we know the earth’s core is molten?
Earthquake measurement
Richter scale
logarithmic
Earthquake measurement
Table 14.2, p. 329
Big earthquakes in human history deaths
Shen-shu, China, 1556, 830,000Tangshan, China, 1976 750,000Lisbon, Portugual, 1755 60,000San Francisco, CA, 1906 (8.3) 700Alaska, 1964 (8.5) 114
The killers are:
collapsefirelandslidestsunami
Safety
Safety
Stay calmGo to under some strong objectIf in open, get away from structures
Before earthquakeBuilding codesZoning lawsGood foundation on bedrockHeavy furniture should be bolted downWater mains compartmentalized