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Welcome Delegates to the 53rd

CCOP Annual Session!!!October 16 – 19, 2017

“The Role of Geosciences in Safeguarding Our Environment”

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Cebu City

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Geohazard Information:An Indispensable Tool for

Land Use Planning and Disaster Risk Resiliency Implementation

RD LEO VAN V. JUGUAN

Mines and Geosciences Bureau 6

53rd CCOP Annual Session

October 2017

Philippine Setting Prone to

GEOHAZARDS

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PhilippinesPorphyry Cu belts

Porphyry Cu belts

• Within the Pacific belt of

tropical cyclone

• Within the Ring of Fire

(average of 20 TYPHOONS A YEAR)

• Within the Earthquake Belt

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Tectonic Map of the

Philippines

Source: PHIVOLCS

Negros

Oriental

Earthquake

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1:50,000 SCALE GEOHAZARD MAPPING AND ASSESSMENT

(2005-2010)

The National Geohazard Assessment and Geohazard

Mapping Program of the DENR Mines and Geosciences

Bureau mandated the conduct of a geohazard mapping

for the country as included in the Medium Term Philippine

Development Plan of 2004-2010.

HIGH LANDSLIDE

SUSCEPTIBILITY Unstable areas, highly susceptible to mass

movement.

MODERATE LANDSLIDE

SUSCEPTIBILITY Stable areas with occasional or localized to

mass movement.

LOW LANDSLIDE

SUSCEPTIBILITY Stable areas with no identified

landslide scars, either active or relict .

HIGH FLOOD SUSCEPTIBILITY Areas likely to experience flood heights

of 1.0 to 2.0 meters and/or flood duration

of more than 3 days. These areas are

immediately flooded during heavy rains

of several hours.

MODERATE FLOOD SUSCEPTIBILITY

Areas likely to experience flood heights of

0.5 to 1.0 meters and/or flood duration of 1

to 3 days.

LOW FLOOD SUSCEPTIBILITY

Areas likely to experience flood heights of

<0.5 meter and/or flood duration of less

than 1 day. These areas include low hills

and gentle slopes. They also have sparse

to moderate drainage density.

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1:50,000 TIGBAUAN QUADRANGLE (ILOILO & ANTIQUE Province)

1:50,000 LANDSLIDE SUSCEPTIBILITY RATING

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STATUS AND UPDATES ON THE GEOHAZARD MAPPING AND ASSESSMENT IN REGION 6

1:50,000 scale (CY 2005-2010)

Assessment

Results

Available at

MGB 6

Geohazard

Maps

Available at

MGB 6

Landslide and

Flood Threat

Advisory

Issued to

LGUs

Assessment

Report and

Maps

Distributed

to LGUs

Aklan

Antique

Capiz

Guimaras

Iloilo

Negros

Occidental

1:10,000 SCALE GEOHAZARD MAPPING AND ASSESSMENT

(2011-2014)

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VERY HIGH LANDSLIDE

SUSCEPTIBILITY Unstable areas, significant areas of

which are affected by mass

movement. Human initiated effects

are usually high.

HIGH LANDSLIDE

SUSCEPTIBILITY Unstable areas, highly susceptible to

mass movement.

MODERATE LANDSLIDE

SUSCEPTIBILITY Stable areas with occasional or

localized to mass movement.

LOW LANDSLIDE

SUSCEPTIBILITY Stable areas with no identified

landslide scars, either active or relict .

VERY HIGH FLOOD

SUSCEPTIBILITY Areas likely to experience flood

heights in excess of 2.0 meters

and/or flood duration of more than 3

days; also prone to flashfloods.

HIGH FLOOD SUSCEPTIBILITY Areas likely to experience flood heights

of 1.0 to 2.0 meters and/or flood duration

of more than 3 days. These areas are

immediately flooded during heavy rains

of several hours.

MODERATE FLOOD

SUSCEPTIBILITYAreas likely to experience flood heights

of 0.5 to 1.0 meters and/or flood duration

of 1 to 3 days.

LOW FLOOD SUSCEPTIBILITY Areas likely to experience flood

heights of <0.5 meter and/or flood

duration of less than 1 day. These

areas include low hills and gentle

slopes. They also have sparse to

moderate drainage density.

1:10,000

MUNICIPALITY

OF LEON, ILOILO

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1:10,000 LANDSLIDE SUSCEPTIBILITY RATING

STATUS AND UPDATES ON THE GEOHAZARD MAPPING AND ASSESSMENT IN REGION 6

1:10,000 scale (CY 2011-2014)

Assessment

Results

Available at

MGB 6

Geohazard

Maps

Available at

MGB 6

Landslide and

Flood Threat

Advisory

Issued to

LGUs

Assessment

Report and

Maps

Distributed

to LGUs

Aklan

Antique

Capiz

Guimaras

Iloilo

Negros

Occidental

Assessment

Results

Available at

MGB 6

Geohazard

Maps

Available at

MGB 6

Landslide and

Flood Threat

Advisory

Issued to

LGUs

Assessment

Report and

Maps

Distributed

to LGUs

Aklan

Antique

Capiz

Guimaras

Iloilo

Negros

Occidental

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DIFFERENCE BETWEEN 1:50,000 and 1:10,000 Scale

1:50 ,000 scale 1:10,000 scale

• Data collected is on Landslide

and Flood susceptibility in the

barangay proper

•Data collected is on Landslide and

Flood susceptibility of puroks/

sitios

• Assesses other important

structures in the barangays, such

as schools, churches, roads and

possible evacuation and

relocation sites.

OBSERVATIONS AND FINDINGS

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RESULTS OF THE GEOHAZARD MAPPING AND

ASSESSMENT (1:10,000 SCALE)

• Based on the 2011 mapping and assessment in

San Joaquin, Miag-ao, Igbaras and Tubungan, all

in the Province of Iloilo, LANDSLIDES and

FLOODING have a significant impact on

agriculture, infrastructure projects and school

structures.

IMPACTS OF LANDLSIDES AND

FLOOD

AGRICULTURE

productive farmlands Less productive

More work intensive

Unusable

INFRASTRUCTURE PROJECTS High Maintenance Cost

Unsafe

Unusable

Abandoned

SCHOOL STRUCTURES Unsafe school buildings

Unsafe evacuation sites

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Day Care Center and Ricefields,

Brgy. Buenavista, Tubungan, Iloilo (2011)

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Approximately 10.5 hectares of farmlands were affected/ destroyed by

the a landslide in Brgy. Buenavista, Tubungan, Iloilo. (2011)

Head

Base

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A hectare, more or less, of farmland affected by a landslide in Brgy.

Signe, Igbaras, Iloilo. (2011)

Ricefields affected by flooding, bank scouring and erosion, Brgy.

Frantilla and Wayang, Miag-ao.

Affected area

Affected area

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• Estimated amount of losses to landslides and/or flooding per hectare every cropping period in case farmlands will be affected by landslides and/or flooding (2011)

Rice Peanuts

I. Production Yield per

hectare Gross Income

2.6 (MT/ha)

PhP 44,200.00

(Selling price at PhP 17/kg)

(USD 884.00)

1624 kg

PhP 41,786.00

(Farmgate price at PhP 25.73/kg)

(USD 835.00)

II. Total Production Cost

- Labor Cost

- Material Inputs

- Drying/Handling/Hauling

Total

PhP 13,670.00

PhP 13,415.00

PhP 1,820.00

PhP 28,905.00

(USD 578.00)

PhP 22,981.00

(USD 451.00)

III. Gross MarginPhP 15,295.00/ha

(USD 306.00)

PhP 18,805.00/ha

(USD 376.00)

INFRASTRUCTURE

PROJECTS

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BACOLOD NATIONAL HIGH SCHOOL, MIAG-AO, MAY 2011

BACOLOD NATIONAL HIGH SCHOOL,

MIAG-AO, AUGUST 2011

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• Repairs of damaged classrooms and

replacement of destroyed school buildings

can be very costly

Project Estimated Cost (PhP)

A. Cost of repairs for damaged school building 20,000 to 200,000

(USD 400 to 4,000)

B. Cost of one typical concrete classroom more or less 500,000

(USD 10,000)

Road

Unsafe and hard to maintain road in Brgy. Dalije, Miag-ao.

RoadRoad

Unsafe and abandoned 4-kilometer road project, Brgy. Bulho and Cumarascas, San

Joaquin, Iloilo. Cost of the road project: PhP10 million(CY 2011.)

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Re-activated Landslides!!!

May and August 2017 landslide in Igbaras, Iloilo

Collapsed portion along Igbaras-Tubungan National Road at Barangays Buga

and Riroan, Igbaras Iloilo as a result of a landslide on May 1-2, 2017.

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The MGB 6 assessed the landslide in Igbaras-Tubungan National Road along

Barangays Buga and Riroan, Igbaras Iloilo on May 3, 2017 in response to the report

and request of LGU-Igbaras to assess the area. In the MGB geohazard

assessment and mapping (1:10,000), the two barangays have generally low to

moderate landslide susceptibility rating while with some portions have high to very

high landslide susceptibility ratings.

Landslide that has reactivated last August 04, 2017 and situated along Igbaras-TubunganNational Road, Both the road and its retainingwalls were subjected to mass movement.

August 4, 2017 - The landslide reactivate in the same area.

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According to the DPWH, the damage caused by the landslide

to the road construction project amounted to P25,000,000.00

(USD 50,000)

Location map of the subject area within Barangay Buga, Municipality of Igbaras. (Source: Igbaras, WesternVisayas, Philippines. 10°44’32.70” N and 122°16’22.90” E. Google Earth)

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Location map of the subject area within Barangay Buga, Municipality of Igbaras. (Source: Igbaras, Western Visayas, Philippines. 10°44’32.70” N and 122°16’22.90” E.)

• Estimated losses for each infrastructures project

damaged/destroyed due to landslides

Infrastructure Projects Estimated Cost (PhP)

A. 4-5 kms. of unpaved farm to market road10 million

(USD 200,00)

B. Gabions (20 meters long, 1 meter wide)

500,000 to 1 million

(USD 10,000 to 20,000)

C. Labor and machine rentals for road

maintenance

at least 10,000/day

(USD 200)

D. Barangay Hall/Plaza/Basketball Court/Chapel100,000 to 500,000

(USD 200 to 10,000)

E. National Road P25 million

(USD 500,000)

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• The unaccounted impacts of landslides and flooding to agricultural areas, infrastructure

projects, education and disaster management to the four landslide-prone municipalities

is EXTENSIVE AND VERY COSTLY.

• It may worsen in the coming years if the proper and necessary mitigating and

adaptation measures are not formulated and implemented.

ProjectSan

JoaquinMiagao Igbaras Tubungan Total

A. Total No. of barangays

assessed45 79 46 48 218

B. No. of barangays with

agricultural areas that are

highly prone and/or affected by

landlslides and flooding

31 68 44 45188

(86.24%)

C. No. of barangays with

infrastructure projects that are

highly prone and/or affected by

landslides and flooding

26 39 33 37 135 (62%)

B. No. of barangays with day

care centers, elementary and

high schools that are highly

prone and/or affected by

landlslides and flooding

16 16 16 17 65 (29%)

THE RELEVANCE OF GEOHAZARD

ASSESSMENT AND MAPPING

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THE BARANGAY CAMANDAG,

LEON, ILOILO EXPERIENCE

June 2008

In 2006, MGB 6 conducted a geohazard assessment of (7) critical barangays in Leon, Iloilo.

Landslide Threat Advisories issued

Lectures were conducted to the residents of these barangays on landslide and flooding susceptibility of the areas

Preparedness and mitigation measures were emphasized

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In June 2008, Typhoon Frank hit Iloilo

Brgy. Camandag was severely affected by landslides

32 houses out of 49 were totally damaged and buried.

Total population is 323.

Brgy. Camandag

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THE GOOD NEWS!!!

THERE WERE NO CASUALTIES IN BRGY. CAMANDAG

DESPITE DAMAGES TO PROPERTIES.

. ..

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THE BARANGAY CAWILIHAN,

LEON, ILOILO EXPERIENCE

August 2011

COMMUNITY APPRECIATION AND

APPLICATION OF THE GEOHAZARD

MAPPING AND ASSESSMENT RESULTS:

THE BRGY. CAWILIHAN, LEON

EXPERIENCE

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BRGY. CAWILIHAN, LEON, ILOILO

About 10.5 kilometers (aerial distance)NW of Leon town proper;

With 56 households;

Located in a ridge, surrounded by steepslopes;

Underlain by highly weathered beds ofsandstone, siltstone and mudstone andalluvium;

BRGY. CAWILIHAN, LEON, ILOILO

Classified as highly susceptible tolandslides during the 2008 geohazardassessment;

The results were discussed with the Punong Barangay and a landslide threat advisory with corresponding recommendations was issued;

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The advisory was posted in the bulletinboard at the barangay hall forreference and information of theresidents;

LANDSLIDE THREAT ADVISORY

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At about past 10:00 A.M. on August 25,2011 ground shaking was felt in the area;

According to PHIVOLCS, an earthquakeoccurred with a 4.5. magnitude and SanJose De Buenavista, Antique as epicenter;

On August 27, 2011, a landslide occuredat Brgy. Cawilihan, Leon at 10:30 p.m.due to strong and continuous monsoonrains brought about by Typhoon Mina.

Head of the landslide - Barangayproper;

Base of the landslide - Sibalom River;

The affected area is about 20hectares;

Eight (8) houses occupied by 11families were totally damaged;

• Rendered 20 hectares of farmland unfit for

rice production.

Portions of the barangay road, moreor less 50 meters long, collapsed;

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BRGY. CAWILIHAN, LEON

BRGY. CAWILIHAN, LEON

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Landslide debris flow into Sibalom River may cause

damming, and its sudden breaching may cause

flashfloods dowstream.

THE GOOD NEWS!!!

• THERE WERE NO CASUALTIES IN BRGY.

CAWILIHAN DESPITE THE SEVERITY AND

EXTENT OF THE LANDSLIDE;

• THE RESIDENTS WERE ABLE TO REMOVE

ALL THEIR BELONGINGS INSIDE THEIR

HOUSES BEFORE THE LANDSLIDE;

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RELEVANCE OF GEOSCIENCE

INFORMATION

• Proper and consistent implementation of the

geohazard mapping and assessment program

can result to:

A. Increased LGU awareness on recognizing

the signs of impending geohazard events in

the likes of rain induced landslides and

floods,

B. Make them understand more the dangers

posed by landslides and floods, and

C. Empowers the community and its populace to

respond accordingly to the situation.

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Installation of community-based

geohazard warning signages

Orientation on Pre-Disaster Risk Assessment

Valderrama, Antique

Miagao, Iloilo

Pavia, Iloilo

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Lambunao, Iloilo

Provide information on susceptibilities of a specific

barangay to landslides and

Option to download the specific

geohazards map (e.g. Masinloc

NAMRIA Quadrangle Map Sheet)

The MGB Geohazards Web Portalwww.denr.gov.ph /www.mgb.gov.ph/ pia.gov.ph / essc.gov.ph

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• Conduct of province- and

municipal-wide information and

awareness campaign

• Distribution of IEC materials on

geohazards (posters, flyers,

comics,videos)

Making people aware through IEC

DILG (TAPATAN 2012)

HLURB Seminars

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Geohazard Presentation for the LCEs (2012)

IN PARTNERSHIP WITH THE OFFICE OF THE CIVIL DEFENSE (OCD), REGION 6

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When the community can relate and

constantly use the results of disaster

preparedness and mitigation

programs of the government, the

negative impacts of natural hazards

can be minimized, and most

importantly, the loss of lives can be

prevented.

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Updating of 1:10,000 Geohazard Maps

Vulnerability and Risk Assessment

(VRA)

1:10,000 Coastal Geohazard Mapping

Detailed Karst Subsidence (Sinkhole)

Hazard Mapping and Assessment

CONTINUING PROGRAMS AND ACTIVITIES

THANK YOU FOR YOUR

ATTENTION!