PU 430 - UNIT 7CHAPTERS 5 AND 6

EARTHQUAKES

Chapter Five

Introduction

One of the most powerful & potentially devastating forces of nature is the energy contained in the Earth’s surface

The violent shaking of an earthquake results from the sudden release of this energy & can collapse buildings, fracture roadways, & create tsunamis

The intensity of these events is measured in two ways: The Richter Scale - A logarithmic measurement of

earthquake intensity The Modified Mercalli Scale - Describes the effects

observed by an earthquake, including how an event is felt by people in the area & the expected damage

Effects on the Human Body

A variety of traumatic injuries may result from an earthquake, including: Minor cuts & bruises Serious burns Fractures Crush injuries Pulmonary challenges

The earthquake-related injuries that pose the most unique challenges are crush injuries

The risk of earthquake death increases with: Age The presence of mental or physical disabilities Lower socioeconomic status

Prevention

Earthquake preparedness is not only possible but essential

Prevention of earthquake associated morbidity & mortality starts with minimizing construction projects in areas known to have high risk of earthquake damage

Enhancing individual & home preparedness requires an effective public education initiative

Hazard Hunts

Minimizing earthquake injury risks in a structure begins with a search for any items that can fall or break & cause injuries

This includes:◦ Heavy items that can fall & injure an occupant◦ Hazardous materials that can be released from spilled

containers or ruptured pipes◦ Electrical hazards from broken or fallen wires◦ Fire risks from gas lines & appliances

Individual Preparedness

A safe spot should be selected in each room of a home, workplace, or anywhere that you spend a considerable amount of time

A plan for immediate action should include practicing the “drop, cover, & hold on” procedure

A safe spot should also be identified outside away from buildings, power lines, & other hazards

Individuals should be trained on basic first aid, the use of fire extinguishers, procedures for shutting off utilities, & communication planning using out of town contacts

Immediate Actions

The most important immediate action is to stay calm

“DROP, COVER, & HOLD” - As soon as the shaking begins, you should immediately drop to the floor, take cover under a sturdy table or other piece of furniture, & hold on

Stay inside until the shaking stops

When exiting the building, avoid using elevators & be aware that the electricity may go out or the fire alarms or sprinkler systems may activate

Public Health Actions

Within 48 hours, environmental health staff conducted a complete survey of food establishments and water potability throughout the City. Throughout the week following the earthquake, environmental health staff disseminated public notices regarding water and sewage conditions in the Marina District. Efforts were coordinated with the Water Department, the Department of Public Works and PG&E to minimize the threat to public health and safety and provide on site information.

Response & Recovery Challenges

The vast majority of those rescued from collapsed structures are done so by untrained individuals nearby who are uninjured & make the decision to assist others

Media advisories are an integral part of the healthcare & public health response

The transition from rescue to recovery is one of the most difficult & controversial issues facing decision-makers when dealing with collapsed structures

A major disaster often has a unifying effect on responders & following a disaster, turf issues & other barriers to preparedness frequently give way to better collaboration that pays dividends for future preparedness efforts

Case Study: Loma Prieta Earthquake

Slide 17. 11, Loma Prieta Earthquake

October 17, 1989:

A magnitude 7.1 earthquake shook

San Francisco and its 7

surrounding counties

(Source: USGS)

(Source: http://www.exploratorium.edu/faultline/engineering/damagemap.html)

Session 17: Disaster Case StudiesCoastal Hazards Management Course

(Source: http://www.seismo.berkeley.edu/seismo/faq/1989_0.html)

(Source: Red Cross )

Lessons Learned: Loma Prieta

Slide 17. 12, Lessons Learned

Since the Loma Prieta Earthquake, greater attention has been focused on:

• Identifying at risk urban areas•Applying mitigation strategies such as seismic retrofitting

(Source:http://www.goldengatebridge.org/projects/seismicsummary.html)

Session 17: Disaster Case StudiesCoastal Hazards Management Course

(Source: USGS)

Retrofitting the Golden Gate

Bridge

FLOODS

Chapter Six

Floods

Floods are nature’s most widespread disaster

The human factors that contribute to flooding are mostly associated with development & land use

In the last century there were over eight million fatalities attributed to floods

Case Study: Hurricane Floyd

Slide 17. 15, Hurricane Floyd

(Source: http://www.dem.dcc.state.nc.us/mitigation/photos1.htm )

Floyd resulted in the Presidential declaration of 13 states as federal disaster areas.

(Source: NCSU)

Session 17: Disaster Case StudiesCoastal Hazards Management Course

Lessons Learned: Floyd

Slide 17. 16, Lessons Learned

The flooding from Hurricane Floyd increased dedication to mitigation planning and outreach efforts Session 17: Disaster Case Studies

Coastal Hazards Management Course

(Source:http://www.dem.dcc.state.nc.us/mitigation/photos2.htm)

Dam & Levee Failure

Even frequent inspections of levee systems cannot guarantee their safety since levee damage is not always apparent

Although dams have excellent social benefits including flood control, power generation, water storage, irrigation, recreation, & more, they have not always been safely maintained

The primary reason for dam collapse is improper design, followed by flooding that exceeds the spillway capacity & foundation problems such as seepage & settlement

Riverine Flooding

The nature of a riverine flood is shaped by the terrain & weather patterns

Two types of riverine flooding include:◦ Common overbank flooding - In regions with relatively flat

terrain, the water is often shallow & slow moving, lingering for days or weeks

◦ Flash floods - Narrow, steep valleys quickly collect floodwaters in a concentrated area making their floods faster moving & shorter in duration, creating a quick rise & intense, destructive flow

Lake Level Fluctuation Flooding

Lake level fluctuations can result in lake area flooding with a variety of effects, including: Shoreline erosion, which can threaten property & homes Floodwater intruding into drinking water sources Septic systems becoming compromised & causing

contamination

Ground Failure & Flooding

Ground failures include a variety of circumstances, including:◦ Landslides - Sometimes block a stream or river & cause

flooding upstream from the site◦ Mudslides - Can focus or redirect debris that can reroute

streams & rivers causing floods◦ Alluvial fans - Fan-shaped deposits of small debris that

occur at the foot of a focused drainage area, usually at the base of a mountain range where it opens up to a plain

Coastal Flooding

Coastal flooding occurs when a powerful low-pressure system drives ocean water inland as a storm surge that exceeds the normal tidal surge

Coastal flooding levels are defined as: Minor – Nuisance coastal flooding of locations adjacent to

the shore Moderate - More substantial coastal flooding, threatening

life & property Major - A serious threat to both life & property

Effects on the Human Populations

The majority of flood related deaths are from drowning

Other causes of death include physical trauma, fire, electrocution, carbon monoxide poisoning, & heart attacks

There are different levels of risk associated with the type & phases of each flood disaster

There are many infectious disease risks associated with the post flood environment, including:◦ Contaminated water◦ Spoiled food◦ Hazardous mold

Prevention

A family preparedness plan should be developed

You should understand your level of flood risk

It is best not to build in flood-prone areas unless it is absolutely necessary & incorporates elevated & reinforced designs

Before a Flood

To prepare for a flood, you should: Avoid building in a floodprone area unless you

elevate and reinforce your home. Elevate the furnace, water heater, and electric panel

if susceptible to flooding. Install "check valves" in sewer traps to prevent

floodwater from backing up into the drains of your home.

Contact community officials to find out if they are planning to construct barriers (levees, beams, floodwalls) to stop floodwater from entering the homes in your area.

Seal the walls in your basement with waterproofing compounds to avoid seepage.

During a Flood

If a flood is likely in your area, you should: Listen to the radio or television for information. Be aware that flash flooding can occur. If there is any

possibility of a flash flood, move immediately to higher ground. Do not wait for instructions to move.

Be aware of streams, drainage channels, canyons, and other areas known to flood suddenly. Flash floods can occur in these areas with or without such typical warnings as rain clouds or heavy rain.

During a Flood

If you must prepare to evacuate, you should do the following: Secure your home. If you have time, bring in outdoor

furniture. Move essential items to an upper floor. Turn off utilities at the main switches or valves if

instructed to do so. Disconnect electrical appliances. Do not touch electrical equipment if you are wet or standing in water.

During a Flood

If you have to leave your home, remember these evacuation tips: Do not walk through moving water. Six inches of

moving water can make you fall. If you have to walk in water, walk where the water is not moving. Use a stick to check the firmness of the ground in front of you.

Do not drive into flooded areas. If floodwaters rise around your car, abandon the car and move to higher ground if you can do so safely. You and the vehicle can be quickly swept away.

Driving

The following are important points to remember when driving in flood conditions:

Six inches of water will reach the bottom of most passenger cars causing loss of control and possible stalling.

A foot of water will float many vehicles. Two feet of rushing water can carry away most

vehicles including sport utility vehicles (SUV’s) and pick-ups.

After a Flood

The following are guidelines for the period following a flood: Listen for news reports to learn whether the

community’s water supply is safe to drink. Avoid floodwaters; water may be contaminated

by oil, gasoline, or raw sewage. Water may also be electrically charged from underground or downed power lines.

Avoid moving water. Be aware of areas where floodwaters have

receded. Roads may have weakened and could collapse under the weight of a car.

After a Flood

Stay away from downed power lines, and report them to the power company.

Return home only when authorities indicate it is safe.

Stay out of any building if it is surrounded by floodwaters.

Use extreme caution when entering buildings; there may be hidden damage, particularly in foundations.

After a Flood

Service damaged septic tanks, cesspools, pits, and leaching systems as soon as possible. Damaged sewage systems are serious health hazards.

Clean and disinfect everything that got wet. Mud left from floodwater can contain sewage and chemicals.

Immediate Actions

The initial actions taken during a flood should first be based upon public announcements & warnings of local officials

Some first steps may be to:◦ Secure your home◦ Move important items & valuables to the highest level of

the structure◦ Turn off utilities using the main switches & valves◦ Unplug electrical appliances

The exception to these suggestions is if you are aware of flash flooding risks - you should then immediately move to a safe location

Response & Recovery Challenges

Once a flood is over, the immediate actions taken will be dictated by local officials & by the observed environmental impact

After a flood evacuation, you should listen closely to news reports that announce when it is safe to enter affected areas

As the affected population begins to reenter the area, it is important to establish a visible support system across the community

Questions?

Read Chapters 5&6 Initial DB postings are due NLT Saturday,

responses are due NLT Tuesday of each week Quiz due 8/21 – NLT Midnight EST

Unit 7 Reminders

Hurricane, Thunderstorms, Tornadoes and Winter Storms Read Ch. 8, 11 & 14

Unit 8 Quiz – Due 8/28 Next seminar – Thursday 8/23

Look ahead to Unit 9 Public Health Emergency Preparedness Simulation Assignment

Using the following template, you will participate in a disaster scenario. Utilizing the ICS structure and research on weather-related incidents, complete sections of the template as directed. You will assume the role of a public health professional and make decisions/prepare documents as needed. All the basic information concerning the disaster is contained in the scenario.

Unit 8 – What’s Coming Up?