The Valley Fault System

Atlas in Greater Metro Manila Area

Valley Fault System • East Valley Fault

• 10 km (M6.2) • Municipalities of Rodriguez

and San Mateo, Rizal • West Valley Fault

• 100 km (M7.2) • Bulacan ((Doña Remedios

Trinidad, Norzagaray and San Jose Del Monte City)

• Rizal (Rodriguez) • Quezon City, Marikina City,

Makati City, Pasig City, Taguig City and Muntinlupa City

• Laguna (San Pedro City, Biñan City, Sta. Rosa City, Cabuyao City and Calamba City)

• Cavite (Carmona, General Mariano Alvarez and Silang)

Evolution of the VFS Atlas • Studies conducted by PHIVOLCS in

1990s and published the 1:10,000 VFS map for Metro Manila and 1:50,000 map for nearby provinces in 2000

• In 2012, PHIVOLCS-DOST revisited the VFS as one component of the project “Enhancing Greater Metro Manila Areas (GMMA) Institutional Capacities for Effective Disaster/Climate Risk Management towards Sustainable Development”, or the GMMA-READY Project, supported by the UNDP and AusAid.

1:10,000

1:5,000

Why remap?

• Larger scale more detailed base maps are available

– More details of the current ground and built-up areas.

• Newly acquired old aerial photographs

1:10,000 1:5,000

Methodology • Interpreted aerial

photograph series – Year 1946, 1966 and

1982

• Translated into 1:5,000 topographic base maps from NAMRIA (2004) 1946 Aerial

Photograph

1:5,000 Topo Maps (MMEIRS, 2003)

Methodology

• Field validation

• Series of peer reviews (Internal and External)

Methodology

The Valley Fault System (VFS) in Greater Metro

Manila Areas Atlas

• 33 map sheets • Metro Manila

• 1:5,000 (22 map sheets) • Laguna and Cavite

• 1:10,000 (10 map sheets) • Bulacan and Rizal

• 1:50,000 (1 map sheet)

Reading the VFS Atlas

Legend

Map Scale

Index to adjoining sheets

Reading the VFS Atlas

Reading the VFS Atlas

Ground rupturing during earthquake was

documented. Topographic features associated

with active fault is clearly evident on aerial

photographs. And with clear transected land

features on the ground.

Hachured: Indicate downthrown areas

Same as solid line (certain trace) but

shows area that moves downward

Solid line: Fault trace is certain

Reading the VFS Atlas

500 m

N

Armed Forces and Police Mutual Benefit Ass. Inc.

Little waterfall

Brgy. Tumana

Dashed line: Fault trace is approximate

Fault whose precise location on the ground cannot be delineated

because erosion, human activity, etc. have erased their traces.

Dotted line: Fault trace is concealed

Fault trace is concealed on the ground by

recent sediment deposits. Usually across

rivers and river deposits, landslide deposits.

Reading the VFS Atlas

• shows fissures that are manifestation of ground subsidence • Largely observed from 1990 to 2000 in Taguig City,

Muntinlupa City, San Pedro City, Biñan City and Carmona.

Reading the VFS Atlas

• active fault coincides

with fissure; hachures

indicate the downthrown

area

Ladejo Subd.

Sto.Niño Subd

Brgy. Putatan

1

1

2 3

2 3

Muntinlupa Institute of Technology

Buffer Zone

The recommended minimum buffer zone, or zone of avoidance, against ground rupture hazard is at least 5 meters as reckoned from both sides of the fault trace or from the edge of the deformation zone.

Useful information for

land-use planning,

engineering and

construction, scientific

research, disaster risk

reduction and

mitigation programs

Contact Us: http://www.phivolcs.dost.gov.ph

/phivolcs_dost

Philippine Institute of Volcanology and Seismology (PHIVOLCS-DOST)

Earthquake & Tsunami (24/7):

Tel. Numbers

+632 929-9254

+632 426-1468 loc 124 / 125

Fax number

+632 927-1087

Volcano (24/7):

Tel. Numbers

+632 426-1468 loc 127

Telefax number

+632 927-1095

IEC materials:

+632 426-1468 loc 128

+632 927-4524