Lecture 9: Technological Hazards & Meteorites

What are some examples of technological hazards?

• toxic gas leak

• nuclear energy plant meltdown

• exposire to hazardous materials

• chemical spill

• infrastructure failure

What is an example of a hybrid disaster?

An earthquake that causes an oil spill from a pipeline

What is the vulnerability to technological hazards?

• death toll is typically low

• vulnerability greatest for those involved in specific industries or transportation systems

• Workers in resource industries (ex. mines) in hinterlands are at highest risk

What are the 3 categories of technological hazards?

1. Widespread

• Long term

• cause cumulative effects

2. Rare events

• airplane crashes

• mine collapses

• shipwrecks

3. Relatively common

• automobile accidents

• poisons

What are cumulative effects?

Conditions that worsen slowly over time as exposure to a concentration increases

• Eventually, the concentration reaches a threshold critical to human health

What are hazards with cumulative effects?

• exposure to radiation

• toxic chemicals

• acid precipitation

• groundwater contamination

How do we calculate risk for infrastructure?

Risk is the probability of failure during the lifetime of the structure

How do we calculate risk for transportation?

Risk is the probability of death or injury per km travelled

How do we calculate risk for industry?

Risk is the probability of death or injury per person per number of hours exposed

Where does radon gas come from?

the natural decay of uranium in rock and soil

How/why is radon harmful?

• When radon is inhaled it decays to polonium and lodges in the lungs where it damages tissues

• It is the 2nd leading cause of lung cancer in North America

• It is difficult to detect because the gas is odorless, colorless and tasteless

How does radon enter homes? When is it more dangerous to ender homes?

• The gas can move quickly through non-saturated soil and can seep into homes

• Basements are at higher risk especially in winter due to reduce air circulation

What are genetically modified organisms (GMOs)?

organisms that have had changes made to their DNA by the transfer of genes

What are the most common GM crops?

1. corn

2. soybeans

3. canola

4. wheat

Why are crops genetically modified?

1. to increase yields

2. to have a greater resistance to:

• extreme changes in temp or precipitation

• herbicides

• pests

• acidic soil

Examples of successful genetic modification: (5)

1. chickens that lay low-cholesterol eggs

2. tomatoes that can reduce the risk of cancer

3. bananas and potatoes to treat viral diseases

4. rice that contains bacteria that can clean up oil and toxic spills

5. citrus trees producing fruit in their first year (normally takes 6)

What are indirect impacts of radiation on people?

• genetic effects

• leukemi

• cancer

• birth defects passed on to children

What are the 2 potential sources of radiation?

1. Mining of Uranium

• produce wastes known as tailings that can be a radioactive hazard

2. Production of electricity

• uranium used in nuclear power plants

Where must nuclear power plants be located?

1. near sources of coolant (rivers or lakes)

2. near a market for electricity

Why is nuclear energy considered a clean source of energy?

Because it does not emit the GHGs that cause climate change

Where are the majority of nuclear power plants located in North America?

Eastern north america

What is a nuclear meltdown?

An accidents that results in damage from overheating

• occurs when the heat generated by a nuclear plant exceeds the heat removed by its cooling systems

• fuel rods turn to liquid and the walls of the plant could melt from the extreme heat

• the hot liquid could melt through the bottom of the plant and seep into the soil

What was the Three Mile Island Nuclear Accident?

• The worst nuclear disaster in US history

• One of the two power plants on Three Mile Island in central Pennsylvania experienced a partial meltdown.

• It was caused by a failure of a valve that controlled cool water entering the plant.

• There were no direct injuries, minor amounts of radiation were released and the plant closed

What was the Chernobyl Nuclear Accident?

• The worst nuclear disaster in world history

• The accident was a result of a flawed design, operator error, and disregard of safety regulations

• An explosion at the plant caused the immediate deaths of three workers

• Within one year, 28 more workers died from extreme radiation exposure.

• Over the following two decades, thousands of people developed thyroid cancer attributed to radiation exposure

Why is nuclear power in higher demand today?

• Because its a clean energy source

• growing concern for GHG emissions

What was the titanic shipwreck?

a passenger ocean liner that struck an iceberg and sank on its maiden voyage on April 15, 1912

Why was the death toll so high (1517) for the titanic shipwreck?

the lack of lifeboats for all passengers

Why are oil spills so devastating?

• because clean-up can take months to years

• oil penetrates bird feathers and mammal fur reducing their ability to insulate

  • birds and mammals left vulnerable to temp changes and makes them less buoyant in water

What caused the Exxon Valdez oil spill?

An oil tanker ship struck a rocky reef off the south coast of Alaska

Why was the Exxon Valdez oil spill so devastating?

• Because the region was an important habitat for salmon, seals, sea otters, killer whales, and seabirds

• 75 million litres of oil spilled

• it was in a remote location which made recovery efforts difficult

What caused the Deepwater Horizon Oil Spill?

An oil rig exploded in the Gulf of Mexico

What was the Deepwater Horizon Oil Spill so devastating?

• the explosion killed 11 workers due to methane rising up through a drill pipe

• Approximately 11 million litres of oil leaked from the well every day for months (was finally capped by cement)

• The spill caused extensive damage to wetlands and beaches along the U.S. Gulf of Mexico coastline

• The tourism industry faced severe economic loss during summer 2010

What is groundwater?

water that is found within the cracks, spaces, and pores in soil, sand, and rock

• fills spaces between soil particles and fractured rock underground

When and why did the Tacoma Narrows Bridge collapse?

1940 → high winds caused the collapse, because the design of the bridge did not provide any open trusses for wind to pass through

When and why did the Baltimore Bridge collapse?

2024 → a container ship lost power, started drifting, and then struck one of the pillars of the bridge

What are the 2 major space shuttle explosions?

1. Challenger

2. Columbia

When and why did the Challenger explode?

The Challenger exploded 73 seconds into its flight on Jan.28, 1986

• all crew members died

• the cause was associated with a rubber O-ring seal

  • It failed to seal a joint leading to the release of hot gas that led to failure of the rocket booster

  • The night before the launch was particularly cold; frost and ice had developed on the rocket

  • It is believed the cold weather reduced the elasticity of the O-ring preventing it from properly sealing the joint.

When and why did the Columbia explode?

Disintegrated on Feb. 1, 2003, upon re-entry into Earth’s atmosphere after 16 days in space

• During launch, a piece of insulation broke off from the external tank

• It struck the left wing and damaged the system that protects the wing from the intense heat produced by atmospheric gases upon re-entry

What is a supernova?

The explosion of a star because it has reached the end of its life cycle

How and when was the solar system formed?

Scientists believe a cloud of gas and dust in space was disturbed by a supernova

• formed 4.6 bya

What is the Nebular Hypothesis?

• The supernova explosion made waves in space

• This caused the formation of a solar nebula (a flattened cloud of gas and dust)

How was the Sun formed?

The centre of the solar nebula grew hotter resulting in the formation of the Sun

How were planets formed?

The outer edges of the solar nebula cooled causing clumps of particles to stick together and form planets

What is a galaxy?

A cluster of billions of stars

What is a star?

A hot glowing ball of gas that generates energy by converting hydrogen to helium

What is the outermost part of the Sun called?

The photosphere

How hot is the core and the photosphere of the sun?

Core → 15,000,000^oC

Photosphere → 6000^oC

What controls the earth’s climate system?

Energy from the sun

What does the solar system comprise of?

• Sun

• Planets

• Moons

• Bolides

How any planets are in our solar system?

8

What is the order of the planets?

1. Mercury

2. Venus

3. Earth

4. Mars

5. Jupiter

6. Saturn

7. Uranus

8. Neptune

What is the life expectancy of the Sun?

10 billion years

What happens at the end of a stars life cycle?

Massive amounts of energy are released as an explosion (supernova)

What is the life cycle of the Sun?

What is a bolide?

An extraterrestrial body that originates in outer space

What are the 5 bolides?

1. Asteroid

2. Meteoroid

3. Meteor

4. Meteorite

5. Comet

What is an asteroid?

A rocky metallic material in space 10 m to 1000 km in diameter originating in the Asteroid Belt (between Mars and Jupiter)

What is a meteoroid?

Similar composition to an asteroid but only up to 10 m in diameter

What is a meteor?

A meteoroid that has entered Earth’s atmosphere

What is a meteorite?

A meteor that strikes Earth’s surface

What is a comet?

These are distinguished by a large glowing tail of gas and dust

Where are comets believed to have come from?

It is believed that comets originated from an area outside the solar system called the Kuiper Belt

How do comets create light?

They create light as gases are released while the comet is heated by solar radiation

What is the most famous comet and why?

Halley’s comet is the most famous because it is visible with the naked eye and passes close to earth every 75 years

• It was be visible in 2061

What is an airburst?

When a bolide explodes at an altitude between 12-50km

Can an airburst still cause damage?

Yes

Example: Tanguska Airburst

• The explosion destroyed over 2000 km² of forest in a sparsely populated area of northeast Russia in 1908

• airburst because no crater ever found

What happened due to the Chelyabinsk Airburst?

A meteor exploded over the city of Chelyabinsk, Russia creating a shockwave

• It was the largest bolide to enter earth’s atmosphere since the Tunguska airburst

• Over 1500 people were injured, mainly from broken glass

What provide evidence of past meteorite impacts?

Impact craters

What is an ejecta blanket?

A layer of debris around a crater consisting of rock fragments that were blown out of the crater upon impact

What is breccia?

Fragmented rock that falls into the crater shortly after impact

What are the 2 types of craters?

1. Simple craters

2. Complex craters

What are simple craters?

Less than a few km in diameter and do not have an uplifted centre

What are complex craters?

Generally greater than 6km in diameter and has a rim that collapses and a centre floor that slowly rises following impact

What is the Manicouagan Crater?

• complex greater (>100km)

• in central quebec

• formed 214 mya

• rim collapsed and the rock has eroded to form a ring-shaped lake

What is the Chesapeake Crater?

• not discovered until subsurface imaging and drilling revealed its presence off the coast of Virginia

• formed 35.5 mya

• overridden by sediment and seawater as sea levels have risen

What are the 3 reasons craters are more common on the moon than on earth?

1. most impacts with Earth are on oceans thus no crater can be produced

2. impacts with Earth’s land have been eroded or buried and therefore have more subtle features than Moon craters

3. Moon has no atmosphere - Small bodies often burn up and disintegrate in earth’s atmopshere before striking its surface

What was the Shoemaker-Levy Comet?

• entered Jupiter’s atmosphere in 1994

• massive amounts of energy were released, and gas plumes were produced as 21 fragments of the comet collided with Jupiter

• after this impact, it was universally accepted that a similar impact could one day strike Earth

Mass extinction effects coincide with what?

Boundaries of geologic periods on the geologic time scale

What causes mass extinctions?

Abrupt changes in climate due to…

1. volcanism

2. bolides

3. human impacts

How many mass extinctions have there been? (not including todays)

5

What does K-T Boundary mean?

K → Cretaceous

T → Tertiary

What caused the K-T Boundary mass extinction?

Abrupt cooling caused by a bolide impact

What went extinct in the K-T boundary mass extinction?

• dinosaurs

• 70% of all plant and animal species

How was the K-T boundary mass extinction determined to be from a bolide impact?

1. Scientists found large quantities of iridium in rock that was dated at 65 million years old

• Iridium is a rare element on Earth, but it is found in bolides

2. The K-T crater was discovered in 1991; it is 180 km in diameter and was found underlying sediment and seawater

• located on the Yucatan Peninsula in Mexico and is referred to as the Chicxulub Crater

How are bolide impacts linked to other hazards?

• trigger tsunamis, earthquakes, landslides

• cause climate change

How are we managing the hazard of bolide impacts on earth?

• The Spaceguard survey program has catalogued all near-Earth orbits larger than 1 km in diameter

• Extending the inventory to bolides as small as 100 metres in diameter is a current objective.

• If a bolide is determined to be approaching Earth, it would be detectable decades in advance

• Using Laser technology → blowing up an approaching bolide will cause fragments to rain down and is not advisable

• Pushing a bolide off course by ramming it with a spacecraft is the recommended approach