Association of Environmental & Engineering Geologists …c.ymcdn.com/.../resmgr/Student_Resources/ggpng_1_landslides_and_… · Association of Environmental & Engineering ... general

Association of Environmental &

Engineering Geologists (AEG)

To join AEG:

www.aegweb.org/join Student membership is Free! Ask about our scholarships.

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AEG is an international professional organization of over 3000 members made up of environmental, engineering, and hydro geologists, and affiliated professionals. Thanks to ______ for allowing me to speak to you this evening. Are any of you geologists? Do you know any geologists? Do you know what geologists do?

We Rock Your World

What Geologists Do and How Our Work Improves Your Life

Association of Environmental & Engineering Geologists Presenter’s Name and Employment

Presenter’s Email Address www.aegweb.org

What is geology? The study of the earth and its processes,

including rocks, soil, water, landforms, and how they all interact.

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Part of the mission of AEG is to inform the general public as to the value of applied geology and to explain to them how they benefit from what we do.

What is applied geology? Applying the knowledge of the earth and its processes that we have learned through the ages to address problems that affect all of us

every day, and to help make our world a better and safer place to live.

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Geology has been used to secure the water we drink; to make the plates, cups, and utensils we eat with; to build the roads we drive on and the buildings we live and work in; to provide the power we use to heat, cool, and run our homes; to find and produce the gas we use in our cars, to ship our food, and to ship products all over the world.

What do Environmental & Engineering Geologists and Hydrogeologists do?

WWW.AEGWEB.ORG

We identify, analyze, and mitigate natural and manmade hazards to protect property, public health and the environment.

We investigate and analyze the earth materials present from the ground surface down into the earth to evaluate their suitability for support of proposed structures and to provide recommendations for foundation types based on subsurface conditions.

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The members of AEG are applied geologists that focus on using our specialized geologic knowledge to provide practical solutions for environmental and engineering projects.

Why is this relevant and important to you? Environmental, Engineering, and Hydrogeologists work

on:

• Natural hazards – landslides, faulting and earthquakes, flooding, sinkholes, volcanoes, and glaciers

• Site Evaluations – investigate sites for design and environmental considerations such as slope stability, seismic hazards, soil and groundwater contamination, and soil and rock properties for construction considerations

• Site Mitigation – design and implement methodologies to clean-up contaminants in the soil and groundwater, and to stabilize earthen materials

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Think about all the things you have done today. Woke up in a stable house, driven on a highway, had a drink of clean water taken from a man-made reservoir. You have been affected by the work of a geologist.

Examples

NATURAL HAZARD PROJECTS:

• Identification and stabilization of landslide hazard areas

• Mapping of faults and earthquake prone areas

• Mapping of flood zones

• Identification of sinkhole prone areas and recommendations for fixing sinkholes

• Evaluations of volcanic activity probability

• Studies of potential glacier recesses

• Studies of potential sea level rise and its effects on man-made structures

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Examples

NATURAL HAZARDS:

Project: North Carolina Geological Survey Landslide Hazard Maps Program

• Increase public awareness of landslide hazards

• ID areas that need a site specific investigation

• Help reduce losses in the event of a landslide by influencing informed decisions

• Indicate high hazard areas for Emergency Response

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In Sept of 2004 the remnants of back to back hurricanes passed over the mountains of NC. Within two weeks, over 400 landslides were triggered in the area. The NC legislature recognized that landslides were a hazard that the citizens of NC needed to become more aware of, and authorized the NCGS landslide mapping program. This program was to (see slide). Six geologists were hired to be on the project team.

North Carolina Geological Survey (NCGS) Landslide Hazard Maps

Peeks Creek Debris Flow Photo courtesy of NCGS

Engineering Geologists Role: • Identify areas of landslide activity • Create models based on soil and rock properties •Educate the public

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In Sept of 2004 the remnants of back to back hurricanes passed over the mountains of NC. Within two weeks, over 400 landslides were triggered in the area. The NC legislature recognized that landslides were a hazard that the citizens of NC needed to become more aware of, and authorized the NCGS ls mp pgm. This program was to (see slide). I along with 5 other geologists was hired to be on this team.

Landslide Inventory Slope Movement – Slope Movement Deposit Geodatabase

As of Oct 1, 2011:

•3,294 Landslides

•3,251 Ancient Deposits

•46 fatalities since 1916

•40 structures destroyed or condemned since 1990

•24 structures damaged since 1990

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We then field verified these areas collecting location data, damage and movement history, geomorphic data, rock and soil information, and hydrology. We would then come back to the office, modify and update the database and model, and repeat until we had our final maps, or reached a deadline, which ever came first.

N.C. Geological Survey Landslide Hazard Maps Slope Movements/Deposits – where landslides have

occurred or are occurring.

Stability Index Map – where landslides might start

Potential Debris Flow Pathways Map – where landslides might go

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During the course of the project, maps were completed for four Western NC counties. The maps we made were a series of digital maps that were meant to be used in a Geographic Information system (GIS) to identify places that may need a more site specific evaluation. The maps created helped landowners or potential landowners have a better idea about the landslide hazards on specific properties, and helped emergency management personnel be more aware of the areas with highest probability of needing help during a heavy rain event.

NATURAL HAZARDS: Rock Slide

Rock slide in Polk County Tennessee on Hwy

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Rock slide when rock is detached from the earth,and slides down the rupture surface. This is an example of a rock slide off of the Blue Ridge Parkway in April of 2003 triggered by rainfall. Boulder is 15 tons and 180 cubic feet (5 cubic meters).

Arizona Land Subsidence Group

Land Subsidence and Earth Fissures in Arizona Publication

Research and Informational Needs for

Effective Risk Management

NATURAL HAZARDS PROJECTS:

Courtesy of AMEC

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Through orchestrated, multidisciplinary research of patterns of groundwater decline, land subsidence, subsurface stratigraphy, and geomechanics of aquifer materials, the Arizona geoscience community markedly improved their knowledge of subsidence and earth fissures. Experts generally recommend that developers steer clear of earth fissures. This, of course, is of little help to home owners whose lands are bisected by gullies that grow larger and more dangerous with every rainstorm.

Subsidence is a Consequence of Withdrawing Groundwater Faster than it can be Recharged

“Subsidence causes permanent inundation of land, aggravates flooding, changes topographic gradients, ruptures the land surface, and reduces the capacity of aquifers to store water” (T.L. Holzer and D.L. Galloway, 2005)

1925

1955

1977 Subsidence at Mendota, CA

USGS Courtesy of AMEC

Impacts of Ground Subsidence

Flood Risk Dam Freeboard Canal Capacity Sewer Capacity Stream Sediment Bank Erosion Channel Avulsion Earth Fissures Groundwater

Contamination Damage to homes and

other infrastructure

Courtesy of AMEC

As you go throughout your week, think about the things you use that may have been

influenced by a geologist. You might be surprised!

Documents

Association of Environmental & Engineering Geologists …c.ymcdn.com/.../resmgr/Student_Resources/ggpng_1_landslides_and_… · Association of Environmental & Engineering ... general