Natural Disasters and Public Works
Earthquakes
Primary Waves (P-waves)
P-waves, or longitudinal waves, are oscillations where solid particles move in the same direction as wave propagation, with speeds between 6 and 13.6 km/s.
Secondary Waves (S-waves)
S-waves, or shear waves, arrive second, producing particle vibrations perpendicular to wave propagation, with speeds between 3.7 and 7.2 km/s.
Magnitude
The energy released during an earthquake.
Intensity
The effect of an earthquake on structures and people, measured by the Seismic Intensity scale.
Seismic Origins
- Tectonic
- Volcanic
- Local
Landslides
Definition
Landslides are sudden or slow displacements of soil or rock masses down a slope.
Human Causes
- Deforestation of hillsides and gullies
- Benching (cuts for quarries, roads, or buildings)
- Construction on weak land
- Lack of water channels and rain management
Natural Causes
- Seismic activity
- Soil and subsoil composition
- Orientation of fractures or cracks
- Rainfall
- Soil erosion
Landslide Types
- Fall
- Rollover
- Glide
- Earthflows
- Mudflows
- Creep
Consequences
- Loss of life
- Building destruction
- Isolated areas
- Flooding from overflowing reservoirs or lakes
- Crop loss
- Ground cracks
- Intense erosion
Public Works
National System Components
- Comptroller General (technical body)
- Government control units (sectoral, regional, institutional)
- Independent external audit firms (appointed by the Comptroller General)
System Powers
- Modernize governance through control, focusing on corruption
- Hold public servants accountable, identifying liabilities (administrative, civil, or criminal), and recommending corrective measures
Technical Standards
Technical standards are requirements, features, components, and procedures for product or service development. Universality is key.
SNIP Goals
- Efficiency: Resource use
- Sustainability: Improve public service quality
- Socio-economic impact: Increase population welfare
Flooding
Concept
Flooding is water occupying normally dry areas, caused by overflowing rivers, heavy rainfall, snowmelt, high tides, landslides, or tsunamis.
Causes
- Natural (weather-related): Rainfall, snowmelt, sea invasion
- Natural (non-weather-related): Sea invasion, snowmelt
- Human-made: Dam breaks
- Mixed: Dam breaks due to weather
Building in Risk Areas
Buildings in high-risk areas should be protected, elevated, or built on undisturbed terrain above flood levels.
Tsunamis
Definition
A tsunami (Japanese: tsu-harbor, nami-wave) is a series of waves caused by a vertical force displacing a body of water.
Causes
Earthquakes, volcanoes, meteorites, landslides, and explosions can cause tsunamis.
Types
- Tectonic
- Volcanic
- Landslide
- Explosion
Classification
- Local: Less than one hour travel time from the source
- Regional: Within 1000 km or a few hours travel time
- Distant: Over 1000 km, often trans-Pacific, taking half a day or more
International Disaster Example: Haiti Earthquake (2010)
A 7.1 magnitude earthquake devastated Haiti in 2010, causing widespread building collapse. The most intense shaking lasted 18 seconds.
Causes of Building Collapse
- Inappropriate materials
- Inappropriate methods (lack of soil studies, disregard for safe zones)
- Failure to follow building regulations
- Earthquake proximity (12 km)
- Surface rupture
Possible Solutions
- Conduct soil studies
- Enforce building regulations based on area suitability
- Use appropriate materials
- Prevent construction of unsafe buildings
- Avoid corruption
National Civil Engineering Errors: Cracking and Collapse
Surveys show 76.21% of buildings have cracking issues, mostly moderate in walls. 14.45% of buildings experience collapse, primarily slight wall collapse due to material detachment.
Prevention
Construction involves changing risks. Training and education are crucial for worker safety. Employers must inform workers about risks and preventive measures.
Weather Disasters
Onset
- Sudden: Earthquakes, avalanches, some floods, tsunamis
- Gradual: Hurricanes, droughts, volcanic eruptions
Duration
- Short to medium: Earthquakes, hurricanes, volcanic eruptions, tsunamis, landslides
- Long: Droughts, epidemics, floods
Origin
- Natural (Geological): Tectonic plate movement, volcanism, crustal fractures
- Natural (Meteorological): Wind, rain, storms, droughts
- Human-induced: Misuse of natural resources
Definition
Weather disasters are caused by extreme weather exceeding normal limits, such as blizzards, storms, cyclones, droughts, hailstorms, heat waves, hurricanes, floods, and tornadoes.
SNIP (National System of Public Investment)
Definition
SNIP certifies public investment project quality through principles, methods, procedures, and standards.
SNIP Model
Identify the problem, then propose and discuss solutions.
Public Investment Project Definition
- Time-limited intervention
- Uses public funds
- Creates, expands, or restores goods or services production capacity
- Generates profits during its lifespan
Project Bank
A computer application to store, update, and publish information on public investment projects in their preliminary stage. Operational since December 2000.