Geohazard Assessment of Leyte ProvinceDOST - Nationwide Operational Assessment of Hazards

BACKGROUND• Supertyphoon Yolanda (international name Haiyan)

• Tacloban City, Leyte

Yolanda’s typhoon path moving west north west

Location Map of Leyte Province. Leyte is highlighted in red. Tacloban is highlighted in blue, while Eastern Visayas (Region VIII) is in yellow.

Tacloban Demographic Data

Image of Tacloban and its surrounding municipalities

2012 Census of Population and Housing (CPH, 2013a)

Materials Used in Building the Occupied Housing Units in Tacloban

Outer Walls

Materials Used in Building the Occupied Housing Units in Tacloban

Roofing

Soil Map for Leyte Province

STORM SURGE SIMULATIONThe JMA Storm Surge Model is a numerical model developed by the Japan Meteorological Agency (JMA) to simulate and predict storm surges mainly caused by tropical cyclones.

Storm trackMaximum wind speed, Central atmospheric pressure, Bathymetry.

Parameters for Storm Surge Modeling

JMA Storm Surge Model of Yolanda

Highest predicted storm surges for November 8, 2013 1:00 pm.

http://blog.noah.dost.gov.ph

NOAA Comet Program Difference between a storm surge and storm tide.

NOAA Comet Program difference between a surge on a steep seafloor and gently-sloping seafloor.

Storm tide height for San Juanico Strait, Tacloban City

Storm Surge Hazard for North of Leyte (READY PROJECT)Source: http://www.geoportal.gov.ph/ (5:01 PM – 09-25-13)

Rain-Induced Landslide Hazard Map for North of Leyte (source: MGB)Source: http://www.geoportal.gov.ph/ (5:25 PM – 09-25-13)

SHALLOW LANDSLIDE SUSCEPTIBILITYSIMULATION

Shallow Landslide Susceptibility Map for North of Leyte

STRUCTURALLY-CONTROLLED LANSLIDE SIMULATIONColtop3D – simulates a 3D model of the DEM showing the dip and dip direction of its different discontinuity sets.Matterocking - computes and estimates the locations where rock instabilities can occur based on the identified discontinuity sets that allow sliding

Potential Rockslide Zones of Tacloban City, Leyte

ALLUVIAL FAN AND DEBRIS FLOW SIMULATION

• Based from the apex of the alluvial

fan in the municipality of Kananga,

Leyte, a total of 13 barangays are at

a risk of debris flows.

Landslide Inventory Map for Leyte

Province

AbuyogAlangalang

AlbueraBontoc

DagamiHindang

HinunanganKanangaLibagon

LiloanMahaplag

MalitbogMatalom

MeridaOrmoc City

Padre BurgosSilagoSogod

St. BernardTacloban

Tomas Oppus

0 5 10 15 20 25

Number of Landslides per Municipality

Abuyog

Albuera

Dagami

Hinunangan

Libagon

Mahaplag

Matalom

Ormoc City

Silago

St. Bernard

Tomas Oppus

0 5 10 15 20 25 30

% Area Affected

Inventory of Landslides in Leyte

Landslide Statistics Map for Leyte

Province

SHALLOW LANDSLIDE SUSCEPTIBILITYSIMULATION

Shallow Landslide Susceptibility Map for North of Leyte

STRUCTURALLY-CONTROLLED LANSLIDE SIMULATIONColtop3D – simulates a 3D model of the DEM showing the dip and dip direction of its different discontinuity sets.Matterocking - computes and estimates the locations where rock instabilities can occur based on the identified discontinuity sets that allow sliding

Potential Rockslide Zones of Tacloban City, Leyte

Portion of Leyte and Southern Leyte Potential Rockslide Zones

Saint Bernard, Hinunangan, Libangon and Liloan Potential Rockslide Zones

Guinsaugon Area Potential Rockslide Zones and Rock Mass Propagation Extent