In order to better prevent a natural disaster from occurring

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         Ted Yu

     SID: 860797319

Section: Friday 11:10-12PM
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Introduction 8.1:

       In order to better prevent a natural disaster from occurring around people or their

homes, they have to abide by six different rules in order to make themselves safer from

becoming victims of a natural disaster. The six rules to abide are to avoid, accept,

anticipate, alter the building, alter the landscape, and alter the process in which natural

disasters would normally occur.

       Avoid talks about avoiding the natural hazards by building away from them.

Natural disasters can’t happen on one’s lawn if someone completely avoids them. This

would apply to houses like those that are built alongside a cliff. Houses along cliffs are

always in danger of landslides unless heavy mitigation is installed. This would also

include building in an area that is prone to flooding because the land is below sea level,

such as in New Orleans. This could also be talking about living in a chaparral or any

other dense natural places with heavy tree growth without the allowance of natural fires

to clear them every so often.

       If people choose to live in a hazardous area, they have to accept the consequences

that might affect them in the future. Sometimes natural disasters don’t happen in one’s

lifetime, and that is good, but if it does they should be ready to understand that they live

in an area that could be affected at anytime. As such, people cannot be cheap and despite

the heavy cost, should buy insurance for whatever disaster-prone area that they might live

in.

       Anticipating a hazard is also important if one chooses to live in a disaster area.

Cities like Los Angeles and San Francisco are already positively predicted to have a

massive earthquake at anytime. These kinds of cities have to anticipate the hazard and
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have a plan to evacuate as well as have spare water and shelter planned to use, even if it

becomes unavailable during an actual disaster. Unless one anticipates that the inevitable

is going to happen, they will be unprepared in case the actual disaster occurs and would

most likely perish.

        In order to prevent buildings from suffering from more damages than they have

to, one should alter the buildings. Altering the buildings could include making it

earthquake-proof, like reinforcing masonry so that bricks don’t fall as badly during a

large earthquake. Buildings could also install many drains so that they don’t flood as

badly during a flood. Sometimes windows are inappropriately placed in areas that are

prone to heavy wind or tornado activity which could cause injury to the occupants inside

the buildings. Other buildings could be built in a way that makes it fireproof, such as

using tile roofs and having stucco walls.

        Some disasters occur because of the area that the house is located in. Because of

this, the landscapes should also be altered. Densely forested areas like the former San

Bernardino Mountains are destined to have an uncontrollable wildfire if conditions are

right—and it did. Residents had to clear the trees as quickly as possible and they still

couldn’t do anything to prevent the fire that burned away every resident’s homes. Other

areas that are in danger are places that have a high slope and enough rain to cause

landslides, such as the coastal regions of California. The hills that homes in California sit

on have to be reinforced by using techniques such as putting shear keys under the hills or

putting lots of rock bolts inside the hills to prevent roll fall.

        The final thing to consider is to alter the process of building and preventing so

that less of the same natural disasters could appear in the future. This kind of mitigation
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could involve installing gravity drains and wells to drain the interior of landslides so that

future landslides can’t occur due to a lack of internal moisture. The landslides could

happen again, but it would also need a batch of new rain. However, if a hill already has

the measures in place it is less likely to come out damaged again in the future. Other

processes could include being careful about dam walls. If a dam wall were to collapse, it

would mean catastrophic consequences for people living downstream from it. Without

carefully checking the building process, buildings could hurt people because of

ignorance. Constructing buildings in un-reinforced masonry, for example, would

absolutely injure everyone living close to the walls as well as people standing next to the

building in case of an earthquake.



Analysis 8.2:



The likelihood of the occurrence of natural disasters that could damage the structure and

its occupants in Alhambra, CA would rank in this order:



1.Earthquakes

2. Flood

3. Landslides

4. High winds

5. Wildfire

6. Volcanic Hazard
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        A large earthquake will rock the foundations of the structure in the future. It is

inevitable. The structure in Alhambra lies near 3 large faults because it is relatively close

to the San Gabriel Mountains and the Whittier Falls. The structure sits on a foundation

made of clay and silt and thus in a large earthquake would be heavily damaged as the

foundation attempts to spread itself out laterally. If the structure were built on bedrock, it

would fare a little better, but it doesn’t, so therefore this is the most danger to the

structure. Also, the building is made out of a mix of concrete and wood, so it is in danger

as well.

        Flooding is possible, but unlikely to cause much damage in the neighborhood of

the structure. The structure is located at a high elevation with a slope of 7.1616°. The

structure is also located to a major wash of Los Angeles that ultimately helps rain water

travel to dump into the ocean. The structure is elevated way above this wash so the

possibility of flooding due to the wash is highly unlikely. The slope of 7.1616° is also

enough to keep the water from sitting in the area for too long and an intricate system of

drains and sewers is in place because the structure is located in a highly urbanized area.

        Landslides are a possibility due to the foundations that the structure sits on but is

unlikely because of the infrastructure that is installed. Alhambra, CA is highly urbanized

and as such has cement installed over the floors which are also paved. Water that pours

into the area doesn’t have a lot of chances to soak into the earth that could cause a

landslide. Also the mean average rainfall in Alhambra, CA is only 18.56 inches. This is

not a lot of rain, and barely passes the threshold of having more than 15” to even consider

the possibility of landslide (assuming there that is no freak storm that makes it rain that

much at one time). The only landslides that are plausible would be due to an earthquake.
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       High winds are very rare but do occur in the area. In 1852, 1918, 1936, and 1983,

there have been minor tornadoes that appeared within 5 miles of the structure. These

tornadoes never actually approached the structure within 5 miles, but the likelihood of

wind damage due to the future is not impossible. The structure has no possibility of

damage due to hurricanes because it lies just east of the Pacific Ocean which is a bed of

cold water. Hurricanes only form when they have a hot source of water to feed from.

South of California, in Baja California, there are hurricanes and storms that frequent the

Western Mexican coast called chubascos. Chubascos form because of the crack of Baja

California in relation to the Mexican mainland. Hot water gets trapped in there which

allows the hurricanes to form. However, these do not have the fuel to travel far enough to

endanger the structure.

       Wildfire and volcanic activity are both things that can’t possibly damage the

structure. There could be instances where wildfire and volcanic activity make living a

nuisance in the structure but it never actually damages it. Wildfires can’t occur because

the structure is located in a heavily urban area. There is no natural greenery around the

structure or any trees with branches hanging over the roof. The streets are paved and the

vegetation is heavily watered with man-made pipes. Volcanic activity that damages the

house is also impossible because the structure is located 175 miles to the west of the

nearest volcano, which is Amboy Crater located in Amboy, CA. The pyroclastic fall of

cinder cone would not be able to reach the structure due to the direction of wind flow

(East, due to the Westerlies).



8.3 Conclusion Analysis
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       Most of the mitigation strategies are already installed for the structure because it

is located in a heavily urban area. The only thing that I can think of that isn’t done to the

best potential is to have more earthquake mitigation. The structure is made of wood and

cement, due to this it could probably use more diagonal braces in the interior of the

building to make the building more unlikely to collapse. Also, the foundations of the

building could probably be set better. Since flooding is not a big risk, there is not much

more mitigation that isn’t already installed. Landslides are not probable because of the

flood drainage systems that have been installed. There are no risks of landslides unless a

heavy earthquake occurs so that can’t be mitigated. Mitigation for high winds would

probably just include moving the locations of windows away from the beds or having

plastic or shatter-proof windows. However, the likelihood of high-wind damage is a rare

occurrence. Wildfires are impossible, but to mitigate it the structure could just water the

vegetation around the area more. The entire exterior of the building is made of stucco so

it has no chance of burning from wildfires anyways. The structure is located too far from

volcanic activity and thus has no need to mitigate for it.

       The only disasters that could damage the structure that don’t already have

mitigation standards in place are therefore earthquakes and high winds. Earthquake

mitigation is costly and would include opening the walls apart to reinforce the wood

frame, and would be costly and would also mean that the occupants have to leave, which

is bad for business. High wind damage is not as cost-dependent because windows are

relatively cheap.