MGB Geohazard-Assessment-Mapping

7/25/2019 MGB Geohazard-Assessment-Mapping

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The MGBThe MGB GeohazardGeohazard Assessment &Assessment &

LIZA SOCORRO J. MANZANO

Supervising Science Research Specialist


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Objectives

identifying areas susceptibleor vulnerable to various

types of flood and landslidehazards

increase public awareness ofsuch hazards in order tomitigate the negative

impacts.


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Major Activities Geohazard mapping at 1:50,000 scale

and 1:10,000 scale


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High landslide

susceptibility

Moderate landslide

susceptibility

Low landslide

susceptibility

Low to moderate flood

Examples of Geohazards Maps (1:50K) covering

Metro Manila and vicinity

Areas affected by less than 1 m

high flood. These are usually

inundated during prolonged and

intense rainfall or extreme weather

condition.

High floodsusceptibility

Areas affected by greater than 1 m

high flood. These areas are usually

flooded for several hours during heavy

rainfalls. Included are landforms of

topographic lows such as active and

abandoned river channels and areas

along river banks.

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Landslide Susceptibility Zones

These are areas where landslide debris could accumulate.These are areas where landslide debris could accumulate.

Areas with low to gentle slopes and lacking tension cracks haveAreas with low to gentle slopes and lacking tension cracks have

low landslide susceptibility rating.low landslide susceptibility rating.

Areas with moderate landslide susceptibility rating haveAreas with moderate landslide susceptibility rating have

inactive/old landslides and tension cracks which are located awayinactive/old landslides and tension cracks which are located away

from the community. These areas usually have moderate slopes.from the community. These areas usually have moderate slopes.

Areas with high landslide susceptibility rating have active/recentAreas with high landslide susceptibility rating have active/recent

landslides and tension cracks that would directly affect thelandslides and tension cracks that would directly affect the

community. Those with steep slopes and drainages that are pronecommunity. Those with steep slopes and drainages that are prone

to landslide damming are also highly susceptible to landslides.to landslide damming are also highly susceptible to landslides.


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Status of the National

Geohazards Assessment

and Mapping

(1:50,000 scale)

Good news

100%

(December 2010)

www.mgb.gov.ph

All 1:50K geohazards

(landslide and flood) maps

can now be downloaded for

free at the following website:

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Objective: Complete thedetailed geohazards mapping

at 1:10,000 scale

Detailed Geohazards

Assessment and Mapping

at 1:10,000 scale

n verse , c esmunicipalities

Accomplishment to date 950

(2011-172, 2012-230, 2013-548)

Target for 2014- 648


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Methodology

Interpretation and analysis of Remote Sensing Data

(aerial photographs & satellite images) and other thematic maps such as

geologic map, drainage map, slope map, vegetation map


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Geomorphological/Geological

Assessment


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Ground Penetrating Radar surveys


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Anecdotal accounts


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Province- and municipal-wide IEC on

Geohazards

Production of IEC materials on

geohazards (posters, flyers, comics,videos)

Making people aware through IEC


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Provided geohazard maps to local government units and advisories to

communities identified as prone to landslide and flood hazards

Enhance awareness on geohazard

maps and information


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Establishment of the Geohazards Operations Center

and Disaster Response Protocols

Updating of the Geohazards Web Portal

Operationalize the early warning and monitoring system of

geohazards


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Assess relocation/ resettlement

sites of communities affected by

disasters nationwide

Assess relocation sites of areas

affected by Typhoon Pablo in

Compostela valley and Davao

Assessment of identified relocation

sites/temporary shelters/evacuation centers

by LGUs

r en a , yp oon o an a n

Region VIII and Subsidence in

Bohol

Assess the suitability of existing

temporary shelters and evacuation

centers by LGUs

ew ataan, omposte a a ey

Relocation Site Assessment

Tubigon, Bohol

Temporary Shelter Site

Assessment


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LANDSLIDE HAZARDS


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Guinsaugon Landsl ide, SouthernL eyte,2006

Compos tela Valley,2002

LANDSLIDE OR MASS WASTING IS

THE DOWNWARD MOVEMENTS OF

EARTH MATERIALS AIDED BYGRAVITY

Cherry Hil l , An tipo lo,1999


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What are the types of mass wastinghat are the types of mass wasting

TYPEVery Slow

(4km/hr)

Flow CREEP EARTH OR MUDFLOWDEBRIS

AVALANCHE

Slip DEBRIS SLIDE OR SLUMP

Fall ROCKFALL


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Debris FlowDebris Flow

2Real, Quezon, 2005

,, ,,


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MudflowMudflow

,, ,,

Former location of chapel

KapataganKapatagan,, LanaoLanao del Norte,2006del Norte,2006KapataganKapatagan,, LanaoLanao deldel

Norte,2006Norte,2006

MGB Geohazard-Assessment-Mapping

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