Mass Wastin

g

WHAT IS MASS WASTING ?

Mass wasting, is the down-slope movement of a mass of sediment and/or rock due mainly to the force of gravity. The "mass" part of the name implies that a somewhat coherent grouping of sediment/rock begins moving downward due to the force of gravity, and usually in combination with some triggering mechanism such as an earthquake or rapid erosion of the base of a slope.

2 TYPES OF MASS WASTING

LANDSLIDE

A landslide involves the movement of large volumes of unstable earth down. It can be caused by a number of phenomena, including seismic activity (i.e. earthquakes), erosion, rainfall, poor soil management, or other factors.

AVALANCHE

An avalanche is the movement of large volumes of snow. It can be caused by vibrations from seismic activity or, in extreme situations, loud sounds as well as by any disruption to the snow.

LANDSLIDE PREVENTION

Keep Existing Vegetation

Maintain Drainage

Build a prudent distance from the top or bottom of steep slopes.

Learn the history of your property.

Don’t irrigate or put drain fields on a bluff

AVALANCHE PREVENTION

Trigger a small avalanche when no one is on the slope.

Study the snowpack by analyzing each layer or using radar technology.

Fences, posts, nets, and windbreaks changes the way snow collects, interrupting the flow of the snow.

Be aware of the changes in the weather and temperature.

LANDSLIDES

Damage from landslides has increased over the last few decades due to more frequent heavy rains, despite extensive work on stabilizing slopes. In the last decade there have been nearly 1,200 landslides a year.

HIROSHIMA LANDSLIDE

Rain-sodden slopes in the outskirts of Hiroshima collapsed in torrents of mud, rock and debris Wednesday, killing at least 36 people and leaving seven missing.

Areas of Avalanche in Utah

AVALANCHE

10 FACTS ABOUT AVALANCHES

• Each year avalanches kill more than 150 people worldwide.• In 90 percent of avalanche accidents, the victim or someone in the victim’s party causes the snow slide.

• The human body is 3x denser than avalanche debris and will sink quickly. When the slide slows, clear air space to

breathe, then punch your hand skyward. Once the avalanche stops, it settles like concrete.

• Unlike its portrayal in movies, noise does not trigger avalanches. Avalanches are caused by four factors: a steep slope, snow cover, a weak layer in the snow cover and a trigger.

• An avalanche is often triggered when a person’s body weight provides just enough extra stress to collapse the weaker layer below.

• Avalanche risk is at its greatest 24 hrs. following a snowfall of 12 inches or more.

• These moving masses can reach speeds of 80 miles/hr. within about 5 seconds.

• Any slope capable of producing an avalanche eventually will. Cracks and whooping sounds are good warnings of a pending avalanche.

• If a victim can be rescued within 18 minutes, the survival rate is greater than 91 percent. The survival rate drops to 34 percent in burials between 19 and 35 minutes.

• The primary cause of death among all people completely buried by an avalanche is asphyxiation (severe lack of oxygen to the body).

THE KENNECOTT COPPER BINGHAM CANYON

THE KENNECOTT COPPER BINGHAM CANYON MINE SITS QUIET AFTER A LANDSLIDE ON APRIL 11, 2013, IN BINGHAM CANYON, UTAH. KENNECOTT HAS SUSPENDED MINING INSIDE ONE OF THE WORLD'S DEEPEST OPEN PITS.

The debris slides falling as fast as 100 mph crashed to earth with such force that they registered as magnitude-5 earthquakes and then triggered 16 smaller quakes where the bedrock cracked.

At more than 970 m deep, Kennecott’s Bingham Canyon mine is the largest man-made excavation in the world. It has been in operation since 1906 and produces 25% of the copper used in the United States. The site has produced more copper than any mine in history. For decades, mine operators have monitored the stability of pit slopes within the Bingham Canyon mine. When the northeastern wall collapsed, the area had been evacuated, there were no injuries; however, several pieces of heavy equipment and critical infrastructure were damaged or impacted. 65 million cubic meters of material was deposited, making the event as the largest non-volcanic landslide to have occurred in modern times.

The Kennecott Copper Bingham Canyon

RESOURCE

http://www.latimes.com/world/asia/la-fg-hiroshima-landslide-20140820-story.html

http://www.cbsnews.com/news/utah-avalanche-was-largest-in-modern-history/

https://www.dosomething.org/tipsandtools/11-facts-about-avalanches

http://www.geosociety.org/gsatoday/archive/24/1/article/i1052-5173-24-1-4.htm