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West IlocosWest IlocosFault SystemFault System

Dummon RiverDummon RiverFault SystemFault System

Divalacan FaultDivalacan Fault

CaslguranCaslguranFaultFault

PFZ:Bangui FaultPFZ:Bangui Fault

PFZ:AbraPFZ:AbraRiver FaultRiver Fault

PFZ:PFZ:Tubao FaultTubao Fault

PFZ:Infanta FaultPFZ:Infanta Fault

PFZ:SibuyanPFZ:SibuyanSea FaultSea Fault

PFZ:Masbate FaultPFZ:Masbate Fault

PFZ:CentralPFZ:CentralLeyte FaultLeyte Fault

PFZ:LiangaPFZ:LiangaFaultFault

PFZ:Mati FaultPFZ:Mati Fault

Tangbulan FaultTangbulan Fault

Mindanao Fault(MF):Mindanao Fault(MF):Daguma extensionDaguma extension

PFZ:EasternPFZ:EasternMindanao FaultMindanao Fault

West Panay FaultWest Panay Fault

CentralCentralNegros FaultNegros Fault

PFZ:Guinyangan FaultPFZ:Guinyangan Fault

East ZambalesEast ZambalesFaultFault

Iba FaultIba Fault

Valley Fault SystemValley Fault System

Lubang FaultLubang Fault AglubangAglubangRiver FaultRiver Fault

SouthernSouthernMindoro FaultMindoro Fault

Tablas FaultTablas Fault

Project AreaProject Area

CentralCentralMindoro FaultMindoro Fault

CentralCentralMarinduque FaultMarinduque Fault

Lake BatoLake BatoLineamentLineament

Northern SamarNorthern SamarLineamentLineament

Southern SamarSouthern SamarLineamentLineament

Cebu LineamentCebu Lineament

East Bohol FaultEast Bohol Fault

Cabanglasan FaultCabanglasan Fault

Davao River FaultDavao River Fault

CentralCentralMindanaoMindanaoFaultFault

LanaoLanaoFault SystemFault System

MF:WesternMF:WesternMindanao ExtensionMindanao Extension

ZamboangaZamboangaFault SystemFault System

Philippine Fault Zone(PFZ):Philippine Fault Zone(PFZ):Dgdig FaultDgdig Fault

Ma

nil

a T

ren

chM

an

ila T

ren

chP

hilip

pin

e Tren

ch

Ph

ilipp

ine T

rench

Neg

ros

Tre

nch

Neg

ros

Tre

nch

Sulu T

rench

Sulu T

rench

Cotab

ato Tren

ch

Cotab

ato Tren

ch

East

Lu

zon

Tro

ugh

East

Lu

zon

Tro

ugh

West IlocosFault System

Dummon RiverFault System

Divalacan Fault

CaslguranFault

PFZ:Bangui Fault

PFZ:AbraRiver Fault

PFZ:Tubao Fault

PFZ:Infanta Fault

PFZ:SibuyanSea Fault

PFZ:Masbate Fault

PFZ:CentralLeyte Fault

PFZ:LiangaFault

PFZ:Mati Fault

Tangbulan Fault

Mindanao Fault(MF):Daguma extension

PFZ:EasternMindanao Fault

West Panay Fault

CentralNegros Fault

PFZ:Guinyangan Fault

East ZambalesFault

Iba Fault

Valley Fault System

Lubang Fault AglubangRiver Fault

SouthernMindoro Fault

Tablas Fault

Project Area

CentralMindoro Fault

CentralMarinduque Fault

Lake BatoLineament

Northern SamarLineament

Southern SamarLineament

Cebu Lineament

East Bohol Fault

Cabanglasan Fault

Davao River Fault

CentralMindanaoFault

LanaoFault System

MF:WesternMindanao Extension

ZamboangaFault System

Philippine Fault Zone(PFZ):Dgdig Fault

Ma

nil

a T

ren

chP

hilip

pin

e Tren

ch

East

Lu

zon

Tro

ugh

Neg

ros

Tre

nch

Sulu T

rench

Cotab

ato Tren

ch

Figure B2.1

Distribution of Active Faults and Trenches in PhilippinesSource: PHILVOLCS (2000)

N

Legend:

City/Town

Roads/highways

Trench-related fault

Collision Zone

Transform Fault

Trench

Dashed line-approximate offshore project

Dashed line-trace approximate;

Active Fault:Solid line-trace certain;

0 100 200km

▲ ▲

▲ ▲

BF-1

PFZ:Gabaldon

PFZ:Gabaldon

segment

segment

East

East

Zanbales F

ault

Zanbales

Fault

Iba FaultIba Fault

PF

Z:In

fanta seg

men

tP

FZ

:Infan

taseg

men

t

Val

ley F

ault

Syst

em

Val

ley

Fau

ltS

yst

em

Central M

arindug

Central M

arindug

FaultFault

Agubang

Agubang

River F

ault

River

Fault

Central

Central

Mindoro F

ault

Mindoro

Fault

TarlacTarlac

San FernandoSan Fernando

MalolosMalolos

ManilaManila

ImusImus

BalangaBalanga

NasugbuNasugbu

BatangasBatangas

LucenaLucena

BoacBoacCalapanCalapan

Project AreaProject Area

InfantaInfanta

Sta.CruzSta.Cruz

PFZ:Gabaldon

segment

East

Zanbales F

ault

Iba Fault

Philip

pin

e Fau

lt Zone (P

FZ

):Infan

ta segm

ent

Central M

arindug

FaultAgubang

River F

ault

Central

Mindoro F

ault

Project AreaProject Area

Tarlac

San Fernando

Infanta

Sta.Cruz

Malolos

Manila

Imus

Balanga

Nasugbu

Batangas

Lucena

BoacCalapan

Val

ley F

ault

Syst

emAntipolo

Marikina

Figure B2.2 Distribution of Active Faults in Southern LuzonBy PHILVOLCS (2000)

N

Legend:

Roads/highways

City/Town

Dashed line-trace approximate

Approximate offshore projection

Active Fault:Solid line-trace certain

0 15 30km

BF-2

14 30'

14 45'

15 00' 121 15' 121121 30'30'121 30'

121 15' 121 30'

PolilloPolilloStraitStrait

Miray R.

Miray R.

Nangka

R iver

Kanan No.1DamKanan No.1DamKanan No.2DamKanan No.2Dam

AIAI

OCOC

YCYC

YCYC

YCYC

NINI

NINI

OLOL

YLYL OCOC

OCOC

QVPQVP

OCOC

AIAIOLOL

QVPQVP

KananKananNo.B1DamNo.B1Dam

Kaliwa-LowNo.2DamKaliwa-LowNo.2Dam

Kaliwa-LowNo.1DamKaliwa-LowNo.1Dam

Laiban DamLaiban Dam

AntipolaAntipola Tanay AreaTanay AreaS

ierr

a M

adre

Sie

rra

Mad

re

Philip

pin

e Fau

lt Zone

Philip

pin

eF

ault

Zone

InfantaInfanta

PillilaPillila

BarasBaras

RosarioRosario

Riv

erR

iver

MarikinaMarikina

MontalbanMontalban

SanSan MateoMateo

Mar

ikin

a

Mar

ikin

a

MoroneMorone

Taytay TaytayPasigPasig

AnsonoAnsono

River

River

TaguigTaguig

CardonaCardona

AntipoloAntipolo

TeresaTeresa

Riv

erR

iver

AgosAgos AfterbayAfterbay WeirWeir

Agos DamAgos Dam

Prov

ince

of

Lgune

Prov

ince

of

Rizal

Province of Q

uezon

Province

ofQ

uezon

Province of R

izai

Province

ofR

izai

Lim

utan River

Lim

utanR

iver

Bosoboso R

iv

er

Mon

talb

anR

ive

r

Province of RizaiProvince of Bulacan

Miray R.

Miray R.

Nangka

R iver

Ago

s

Ago

s

Riv

er

Riv

er

Kal

iwa

Kal

iwa

Lenatin River

LenatinRiver

Angat River

Angat River

Polillo Strait

Lamon Bay

Laguna de Bay

Kanan No.1DamKanan No.2Dam

Ago

s

Riv

er

AI

OC

YC

YC

YC

NI

NI

OL

YL OC

OC

QVP

OC

AIOL

QVP

KananNo.B1Dam

Kaliwa-LowNo.2Dam

Kaliwa-LowNo.1Dam

Laiban Dam

Antipola Tanay AreaS

ierr

a M

adre

Philip

pin

e Fau

lt Zone

Infanta

Sta.Maria

Pillila

Baras

Rosario

Riv

er

Marikina

Montalban

San Mateo

Mar

ikin

a

Morong

Taytay Pasig

Angono

River

Taguig

Cardona

Binangonan

Antipolo

Teresa

Famy

Riv

er

Kal

iwa

Agos Afterbay Weir

Agos Dam

Prov

ince

of

Laguna

Prov

ince

of

Rizal

Province of Q

uezon

Province of R

izai

Lenatin River

Lim

utan River

Bosoboso R

iv

er

Mon

talb

anR

ive

r

Province of RizaiProvince of Bulacan

Miray R.

Nangka

R iver

Angat River

YL

Based on Nippon-Koei & Lahmeyer International (1992)

N

Figure B2.3 Regional Geological Map

0 5 10km

Legend:

Geologic Boundary

Fault

Dioritic Intrusions

Cretaceous-Miocene-Older Reef Ilmestone

Cretaceous-Miocene-Older Clastic,Volcanic and Volcanoclastic Deposits

Mioccene-Younger Reef

Mioccene-Younger Clastic Series

Pleistocene-Young Volcanic andPyroclastic Deposits

Alluvial DepositsAI

QvpQvp

YCYC

OCOC

OLOL

NINI

TLTL

Qvp

YC

OC

OL

NI

YL

BF-3

10 km Distance

from Agos Dam Site

Agos Dam Site

F7

F5

F1 F3

F2

F6F8

F4

Philippine

Fault Zone

(InfantaFault)

1,000m 0 1,000 2,000 3,000 4,000 5,000

LEGEND

Class I : Active faultIt's certainly active fault.

Class II : Assumed active faultIt's almost certainly active fault.

Class III : Any clear factor is not observedthat indicated by active fault.

Factor of active fault

Certainly of active fault

Fault bulge

Triangular slope

Misalignment of river

Distribution of the Active Fault around the Agos Dam SiteBased on the analysis of aerial photographs

Figure B4.1

BF-4

BF-5