) Tilting = uplifted on one side

2) Tilting = uplifted on one side

ex: Sierra Nevadas (central Cal.)

b. Reverse Fault = upper (hanging wall) block goes up
P. -due to compression ex: L.A County

P. 1). Thrust Fault = low angle…

-extreme pressure. ex: Rocky Mtns.

3. Strike - Slip Fault
-horizontal motion of blocks… pass each other

-like small Transform.....
P.
a. Left - Lateral = other side moves to left
b. Right-Lateral =other side moves to right
P. ex: San Andreas Flt. + most Calif. Flts.

4. Oblique Faults (=diagonal) common=most So. Cal. flts.
-both vertical and horiz. motion combo
P.

A. Southern California Faults + Mtn.s
= most are a combo of rt. Lat. & Reverse faulting
-Why? S.Andreas Flt has double bend.

1) co.cr. colliding = creates mtn.s (mini-Himalayas)

ex: S. Gabriel Mtn.s …tallest & steepest mtns. in So.Cal.

2)several faults parallel to S.A.Flt. =

- cr. blocks ~20 mls. across

- forms most mtn. ranges + islands

EarthQuakes (Ch. )
I. Seismology
Earthquake=vibration…sudden release of energy along fault

P. -starts in one place.......unzips......

Fault (fracture caused by crust movement).

A. Epicenter =pt. on surface above Q’s “focus”

P. 1. Focus = pt. In crust where rupture starts
a. Shallow focus = most quakes (0 –10 ml. deep)
-greatest destruction…… ex. Calif.
b. Deep focus = 40-400 ml. deep =subd. zones

ex. Japan, Oregon

B. Seismograph –detects+measures Q.s

P. - heavy weight stays still during Q…….
1. Seismogram –drawn on paper, since 1880s
P. -measures: when, how long, how strong

C. Elastic Rebound…rock…
-blocks bend until rupture during Q.

P. = snap back into original shape
1. Offset both sides move, displaces features

P. ex. canyons, roads,pipelines & aqueducts...........
2. Fault Creep =both sides move continuously
CD-ROM -no Q, rare ex: Mid. S. Andreas Flt........

D. Quakes = temblors, tremors, seismicity, jolt, shock, skake

1. Foreshocks -only 3%……rare (ex. Japan 2011)

2. Main Shocks -biggest (1/2 energy released)

3. Aftershocks -“always” smaller (all = other ½ energy)

E.Seismic Waves –started by Q
1. Types –travel different ways + speeds
a. P-waves -primary, arrives 1^st
P. -move like slinky or sound (weak)

-can't be felt by us.
b. S-waves -secondary, arrives 2^nd

- (move like rope -also weak)

c. Surface waves – arrive last…we feel !
-move like ocean waves =most destructive!
-all 3 seen on seismogram = both time + intensity

2. Locating Quake Epicenters
-P waves go ~ twice speed of s-waves

P. a. P-S time interval –difference between arrival times

on a seismogram.

P. b. Travel/Time graph = get distance to quake

P. c. Draw circles on map = “ “ “ “

circles from 3 locations……find epicenter at intersection

F. Intensity+ Magnitude

1. Mercalli Scale = measures “intensity” (…..feels)
P. -damage measured in Roman numbers (ex. XII)
-put on map , depends on:

1. Magnitude

2. Distance

3. Ground material
4. Duration

(5. Construction)

- Trinet.org = So. Cal. only, internet….. known in minutes

2. Richter Magnitude Scale
P. -measures total energy of Q…strength
-based on max. amplitude of s-gram
-logarithmic scale=
* * each 1.0 on scale = 10x shaking (= 30x energy)
P.

P.