Earthquake Damage Workshop/Training on Earthquake Vulnerability and - - PowerPoint PPT Presentation

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

Earthquake Damage

Workshop/Training on Earthquake Vulnerability and Multi-Hazard Risk Assessment: Geospatial Tools for Rehabilitation and Reconstruction Efforts Siefko Slob

Overview

• 1. Damaging effects of

earthquakes

• 2. Damage assessment:

case study

• 1. Damaging effects of earthquakes

Direct effects

Ground failures or instabilities due to ground failures Vibrations transmitted from the ground to the structure

Indirect effects

Consequential phenomena

Direct effects of earthquakes

Ground failures (or instabilities due to ground failures)

Surface faulting or fault rupture/movement Vibration of soil (or effects of seismic waves)

Ground cracking Liquefaction Ground lurching Differential settlement Lateral spreading Landslide

Vibrations transmitted from the ground to the structure – Site effects

Causes most damage!

Ground failures

Surface faulting

Ground displacement Ground cracking Ground lurching

Surface faulting

Normal fault. Scarp near Beni Rached. 1980 El Asnam Earthquake, Algeria

Surface faulting

Bent rails of the railroad between Guatemala City and Puerto Barrios caused by the 1976 Guatemala Earthquake

Surface faulting

The 17 August 1999, Izmit Earthquake Displacements from SAR Interferometry

ENVISAT inSAR

Kashmir Earthquake 8 Oct. 2005 Vertical displacement

Vibration of soil: Liquefaction

Displacement and tilting of houses due to soil liquefaction in the Turnagain Height area of Anchorage during the 1964 Alaska Earthquake

Vibration of soil: Liquefaction

Tilting of apartment buildings at Kawagishi-Cho, Niigata, produced by liquefaction of the soil during the 1964 Niigata Earthquake

Vibration of soil: differential settlement

One-story masonry house in a main housing development in the town of Caucete, damaged due to differential settlement caused by liquefaction in the 1977 Caucete Earthquake, Argentina

Direct effects: landslides due to topographic amplification

Santa Tecla (Las Colinas) landslide, Jan 13 2001 earthquake, El Salvador

Direct effects: landslides (Kashmir)

Indirect effects of earthquakes, consequential phenomena

Tsunamis Seiches Floods Fires

Indirect effects: Tsunamis

Near-shore or undersea earthquake causing sudden (vertical) movement of the seafloor As wave approaches shallow water, it slows down, but energy remains constant, causing waves to increase in height (up to 30 m.)

26 December 2004 Sumatra Tsunami

Indirect effects: seiches

Within lake, bay, harbour – enclosed water body “Bathtub effect”

Indirect effects: flooding caused by regional subsidence

Izmit (Kocaeli) Turkey Earthquake, August 17, 1999

Indirect effect: fires

Fire in central Kobe Large fires following strong earthquakes have long been considered to be capable of producing losses comparable to those resulting from the shaking 17 January 1995, Kobe Earthquake

Vibrations transmitted from the ground to the structure

Structural damage:

Torsion Soft storey Pounding Short column

Caused by “site effects”:

Resonance, soft ground effects Topographic amplification

Torsion

Irregular layout or wrong distribution of weights can create large torsional stresses, resulting in damage and/or failure

Plan view

Torsion

Lack of torsional resistance in the columns at the periphery of the building Armenia, Colombia 25 January 1999, Quindío earthquake, Colombia M 6.2

Soft storey

Soft storey: stiffer structural elements which are present in the upper stories are missing at the ground floor - Gujarat earthquake, 26 Jan 2001

Soft storey

The ground floors of many buildings in Turkey are open spaces reserved for stores and show rooms, with insufficient numbers of columns to support the upper floors – Duzce, Izmit earthquake, 17 August 1999, Turkey (MW 7.5)

Pounding

Impact damage Asymmetry

28 February 2001, Mw 6.8 Nisqually, Washington Earthquake

Pounding

Armenia, Colombia 25 January 1999, Quindío earthquake, Colombia M 6.2

Short column

Short column

Balcony and inserted brick wall cause short column failure, in combination with bad detailing (lateral reinforcement) - Armenia, Colombia

Detailing

Insufficient transverse reinforcement to prevent buckling of the vertical reinforcement Unsufficient lateral reinforcement, bad concrete quality, discontinuity

Masonry

Insufficient cohesion

• f the masonry walls

due to weak mortar

• r the absence of

mortar

Stone masonry: behavior during an earthquake

Picture: NSET

• 2. Damage assessment

Case study: Armenia, Colombia Rapid Inventory of Earthquake Damage (RIED project) Assessment of the damage of the 25 January 1999 Earthquake in Armenia and Pereira, Colombia

Objectives

Rapid assessment of the damage inflicted by the 25 Jan 1999 earthquake (M 6.2) To make recommendations for the reconstruction of the buildings and structures in the damaged areas

Means

High resolution aerial photographs Integration of existing and new data in an information technology environment to allow fast analyses and visualization for reconstruction

Location map

Earthquake damage inventory by aerial photographs - Methodology

Fly survey as soon as possible after the earthquake before repair and clean-up takes place Create ortho-rectified digital airphotos for fast on-screen damage assessment

For this a detailed DTM should be available!

Use cadastral maps for base information on building or building blocks footprints and possibly information on building type, age, construction, etc.

Earthquake damage inventory by aerial photographs - Methodology Structures on aerial photographs were marked in 5 classes:

Total Collapse Roof Collapse Roof Partly Damaged No Damage Visible but Rubble in the Street No Damage Visible

Total collapse

Roof collapse

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

earthquake damage map for the entire city

Comparison Aerial Survey – Ground Survey

Reasonable correlation for the highly damaged structures such as structures that completely collapsed or for structures of which roof and partially the walls collapsed. Less correlation for structures with less severe damage.

Results Aerial Photographs Damage Inventory

For reconstruction purposes the inventory gives a good impression of the damage and of major geological, geotechnical, and morphological features that have influenced the damage inflicted on surface structures The presence of such features can then be considered in the planning for reconstruction.

Results Aerial Photographs Damage Inventory (Cont.)

The results of an inventory of damage by aerial photographs can be available more rapidly after an earthquake, as compared to a ground survey. This is of great benefit for relief operations and for reconstruction planning.

Exercise – day 5

Landslide mapping in the Muzzafarabad area using

Aster (15m) VNIR multispectral imagery Quickbird (1 m) optical imagery

Aster (15 m) VNIR multispectral 18/10/2005 Level 3b Orthorectified by ERSDAC (JAPAN)

Quickbird (1m) From spacemaps by DLR (Germany)

Method: on-screen digitising

• 1. Create segment

boundaries

• 2. Label segments
• 3. Correct errors (close

polygons)

• 4. Create polygons
• 5. Label polygons