lecture 8

Question 1

Global seismic risk

Answer 1

number of earthquakes has not increased but the fatalities have, due to urbanization and population growth

Question 2

mitigation

Answer 2

preventing future hazards or reducing their effects

Question 3

building materials effect on earthquakes

Answer 3

1. masonry buildings are especially weak when subjected to horizontal shearing
2. wood is more flexible and better off than brick
3. steel is the strongest but expensive (best for large buildings)

Question 4

building design on earthquakes

Answer 4

• small residential buildings may slide off foundation
• soft first story weakened through garages
• resonance of building

Question 5

corner brackets

Answer 5

strengthen building design

Question 6

seismic retrofits

Answer 6

strengthen builidng after it has been built

ex. historal masonry buildings in Canada

Question 7

2 ways to strenghten building design

Answer 7

ensure cripple wall is built properly

fassen building to foundation

Question 8

resonance

Answer 8

natural frequency of vibration
depends on:
- size, weight distributoin, shape, materials, foundations

Question 9

relationship of height vs resonance frequency

Answer 9

short- high freq
medium- medium
tall - low freq

Question 10

relationship of frequency and stories

Answer 10

buildings resonate at 10Hz/ # of stories
ex. 1 story vibrates at 10Hz
2 story vibrates at 5Hz
10 story vibrates at 1Hz

Question 11

relationship of seocnds and Hz

Answer 11

10Hz / 50 stories = 5 seconds

10 Hz/ 10 stories = 1 second

Question 12

Mexico city earthquake (2017)

Answer 12

Mw 7.1 earthquake 130km south focued damage on <6 story buildings and 370 people died

Question 13

shock absorbers

Answer 13

reduce resonance and dampen shaking

Question 14

base isolation

Answer 14

sepearte building from the ground and place ball bearings, wheels or shock absorbers to absorb energy
ex. vancouver Qube

Question 15

preparedness

Answer 15

preparing to handle the next earthquake before it happens

Question 16

earthquake prediction

Answer 16

specify location timing and magnitude of future shock

- rely on precursor signals and must pass statistical test

Question 17

4 factors forecasts rely on

Answer 17

1. mapped location of active fault
2. rates of strain on faults
3. past average reccurence intervals
4. assumption about range of magnitude faults can generate

Question 18

what is the pateloseismic recordfor cascadia

Answer 18

• was established through coring turbidite deposits

- 50 year forecase predicts Mw 8-9 as 12-33%

Question 19

earthquake early warning

Answer 19

detects quick body waves and sends signals to process location and magnitude of earthquake then send information to city within a few seconds before damaging surface waves

Question 20

earthquake education

Answer 20

drop cover and hold on
get to higher ground
prepare earthquake kit
secure tall furniture
structural engineer
earthquake ensurance

Question 21

factors most imoprtant to estimate the damage caused by earthquake that has just occured

Answer 21

location, depth, building inventory, season/weather (liquefaction), magnitude, intensity distribution

Question 22

PAGER

Answer 22

prompt assesment of global earthquakes for response

• quickly determines population exposed to different levels of shaking
• estimates # of fatalities and economic cost

Question 23

remote sensing

Answer 23

looking at earthquake from satelites or radars

can quickly assess damage