Reclamation Part II

7/30/2019 Reclamation Part II

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Philippine storm surges reported by PAGASA


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Reclamation

area

Ocean front of this reclamation would experience stormsurges as high as 4 meters (13+ feet) increasing asclimate change increases the strength of typhoons.

Large storm waves would ride on top of these surges.


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http://www.nhc.noaa.gov/surge/

Storm surges are worse if they happen at high tide.This increases the difficulty of predicting storm surge size,requiring weather forecasts accurate to within a few hours.


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Storm surge

Pinakamapanganib ang storm surge kung mababa ang dahilig

ng lupa sa ilalim ng dagat, kagaya sa Manila Bay.

Steep seafloor

Gently sloping seafloor


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Typhoon Patsy 14-22 Nov 70

Typhoon Ora 22-30 Jun 72

Ocean-going freightersparked on Roxas Boulevard

by Patsy and Ora


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3. Liquefaction during

earthquakes

In water-saturated material

such as natural bay fill orreclamation, the solid grainsnormally are touching. Thelower grains bear the weightof grains and buildings on topof them.

But during the minute that an

earthquake lasts, the shakingbreaks the contact betweengrains. Together, the solidsand water behave as a slurry,or liquid without strength.Buildings sink or topple into it.

l


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Sand boilsLiquified sand comes up to the surface during the earthquake


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Mexico City, 1985


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Coastal areas underlain by natural

sediment and artificial reclamationfill are particularly susceptible toliquefaction during earthquakes.

This is true for Californias Bayarea as well as Manila Bay.


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Northeastern San Francisco California

Most vulnerable areas are naturalbay fill and reclaimed areas


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Liquefaction in the Marine District in San Francisco,Calif., caused damage during the October 1989 LomaPrieta earthquake.

R l ti s i M il B ld t i


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Reclamation areas in Manila Bay would not require anearthquake to occur nearby to suffer serious damage.Manila was the city hardest hit by the magnitude 7.3earthquake in 1968. Its epicenter was in Casiguran,

Quezon, 225 kilometers away. Many structures thatwere built on river deposits near the mouth of the PasigRiver suffered severe damage from liquefaction. The six-story Ruby Tower in Binondo collapsed, killing 260 people.

f h 1 0 h k


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Lessons from the 1990 earthquake

Epicenter: Near Rizal,northeast of

Cabanatuan, Nueva Ecija

Major damage: Baguio City100 kilometers away

Dagupan, Pangasinan,100 kilometers away

D P i 1990


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Dagupan, Pangasinan 1990

Reclamation Part II

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