Term
| what are four qualities of the CC earthquake that affected how destructive it was to the city of CC? |
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Definition
4 qualities of CC earthquake that affected how destructive it was to the city
1. it was shallow, and close to CBD
2. high radiated energy for a 6.3 mangitude earthquake
3. directivity of rupture was towards CBD
4. local ground affects like basins may have enchanced strong ground motion |
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Term
| what three seismological characteristics influence distribution and severity of damage the most? |
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Definition
the three seismological chacterisitcs that infleunce severity and distribution of damage the most
1. PGA
2. duration of shaking
3. frequency content |
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Term
| which leads to more PGA, vertical or horizontal displacement? |
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Definition
| vertical displacement leads to more PGA than horizontal displacement |
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Term
| how is the direction of displacement connected to PGA? |
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Definition
| veritcal displacement leads to a higher PGA than horizontal displacement |
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Term
to figure out expected PGA, look at these four things
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Definition
to figure out what the predicted PGA for a certain quake is, look at
1. predicted Mw
2. distance from quake
3. geology. How rocks will carry waves, dry vs wet, solid rock vs granular, etc
4. direction of displacement. vertical displacement leads to a higher PGA than horizontal displacement |
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Term
| what is seismic amplifacation? |
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Definition
| seismic amplification is when waves from earthquakes are concentrated on a certain area |
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Term
| foucusing of seismic energy is called what? |
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Definition
| focusing of seismic energy is called siesmic amplification |
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Term
| where is seismic amplifacation likely? |
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Definition
| seismic amplifacation is likely over weak sediments, over basins, or near basins |
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Term
| duration of shaking at a certain site depends on what three things? |
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Definition
duration of shaking at a site depends on three things
1. Mw
2. rupture process
3. geology. basin affects, where siesmic waves rattle around in a confined area, will increase duration of shaking |
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Term
| draw topographic amplifacation |
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Definition
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Term
| draw topographic amplifacation |
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Definition
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Term
| what phenomenom causes boulders to jump? |
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Definition
| the phenomenom that causes boulders on hilltops to jump from one spot to another is topographic amplification |
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Term
| to predict frequency, what 4 things do you need to know? |
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Definition
to predict frequency you must know
1. Mw of expected quake
2. distance from fault
3. expected fault rupture processes
4. geology, how rocks will transmit waves |
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Term
| draw liquefaction happening to a bunch of particles in a box |
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Definition
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Term
| two materials what will undergo liquefaction |
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Definition
two materials that will undergo liquefaction are
1. coarse silt
2. find sand |
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Term
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Definition
| the takeway from that picture of a paleodike is that multiple sand blows have taken the same path during paleoliquefaction. dating the sediments gives insight to recurrence interval |
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Term
| what two factors determine if liquefaction will occur |
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Definition
| PGA is the big determinant of whether liquefaction will occur. duration of shaking matters too |
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Term
| how can liquefaction affect river flood risk? |
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Definition
liquefaction had a twofold impact on river flood risk in CC
1. it narrowed the river channel, reducing the amount of water needed to overflow banks
2. it caused floodplains to subside |
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Term
| without isotope dating or cross cutting relationships, what are 2 ways to figure out the relative ages of sediments in a paleodike? |
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Definition
without isotope dating, there are two good ways to figure out the relative ages of sediments in a paleodike
1. look for levels of redness from oxidation. the older the sediment, the more water tables have passed through, the higher the level of oxidation
2. look for bioturbation. more bioturbation means older
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Term
| human impact on subsidence and liquefaction |
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Definition
| humans disrupted the subsidence/deposition pattern. the way it naturally works is that subsidence would occurs, and then rivers would deposit more sediment and build the land back up. Humans changing river channel patterns means the ground is just gonna sink and sink, and relative SL will rise |
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Term
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Definition
| the reason liquefaction was so widespread from a small earthquake is has to do with the susceptibility of sediment, and seismic amplifacation |
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