Tuesday, September 9, 2014

IAEG in Torino, Italy

So, on Thursday I’m off to Torino, Italy for the IAEG 2014 Congress (IAEG is the International Association for Engineering Geology and the Environment). This conference only happens every 4 years, and it’s a big one with lots of really good applied geology presentations. The theme of the conference is ‘Engineering Geology for Society and Territory’.

I have a poster presentation on Thursday (September 18) in the morning poster session. My presentation is titled “Investigative Procedures for Assessing Subsidence and Earth Fissure Risk for Dams and Levees”. The full abstract is posted below for those that are interested. There is a paper included in the conference proceedings, but it’s really just an extended abstract. My colleagues and I have a series of papers that we authored for the USSD (United States Society on Dams) Conference that was in Phoenix in 2013 that cover the topic in much greater detail.

One exciting part of this meeting (other than being in Italy!) is that AEG is proposing to host the next IAEG Congress in 2018 in San Francisco. I really hope that it’s selected as it will be a great meeting to bring to the US for the first time and a spectacular setting. I’ll post the results of the selection here and on Twitter when it comes through.

Speaking of Twitter, I plan to ‘tweet’ regularly while in Italy (probably at odd hours for US folks), so tune in at @AEGFergason for updates.

Abstract for the meeting below:

investigative procedures for assessing Subsidence and earth fissure risk for dams and levees
Kenneth C. Fergason, PG
AMEC Environment and Infrastructure, Inc.
Michael L. Rucker, PE
AMEC Environment and Infrastructure, Inc.
Bibhuti B. Panda
AMEC Environment and Infrastructure, Inc.
Michael D. Greenslade, PE
Flood Control District of Maricopa County

The depletion of groundwater resources in many deep alluvial basin aquifers in the Western U.S.A. is causing ground subsidence, as it does in many regions worldwide. Ground subsidence can severely and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to undermine the foundations of dams, levees, and other pertinent structures and cause system failure.
Earth fissures that have been exposed to flowing water will most likely have observable surficial expressions such as ground cracking, piping holes, vegetative and tonal lineaments, and similar features, however uneroded earth fissures often do not have surficial expression.

Subsequent to the performance of an evaluation of the overall subsidence experienced in the vicinity of a subsidence-impacted structure, a detailed investigation to search for earth fissures must be performed. Such an investigation must include investigative techniques capable of detecting earth fissures that do not have significant surficial expression. Utilizing the findings of subsidence investigation, additional investigative methods for earth fissure search include photogeologic (lineament) analysis, assessment of the capability of near-surface soils to develop an earth fissure, assessment of the degree of ground disturbance, detailed site inspection, seismic refraction profiling for concealed earth fissures, and excavation of trenches.

Satellite-based interferometry by repeat pass synthetic aperture radar (InSAR) provides unique information about active land subsidence over large areas based on multiple radar images (commonly about 100x100 km scenes) obtained from different time periods. The subsidence or deformation image known as an interferogram can also reveal with proper interpretation some preliminary subsurface information about alluvial basin geometry, lithology and hydrology where active land subsidence is interpreted. However, utilizing interferometry is very a complex task that requires synthesis of available information to properly or best constrain an interpretation.

Effective subsidence risk assessment and mitigation requires understanding and quantification of historic subsidence, and estimation of potential future subsidence that could impact the dams and levee infrastructure.  A primary subsidence mechanism is increasing effective stress due to groundwater level decline within saturated compressible basin alluvium.  Ultimate subsidence magnitude at a given location is a function of change in effective stress, compressible alluvium thickness and material modulus.  Modulus is typically a function of depth and effective stress.  Subsidence rates are assumed to largely be a function of rate of groundwater level decline, alluvium permeability or hydraulic conductivity and distance from groundwater level stress points (such as pumping wells).  Basin alluvium and bedrock interface geometry, and changes and interfaces in basin alluvium lithology, profoundly influence patterns and the degree of subsidence.  Characterization includes collection and synthesis of historic survey and well data, surface geophysical methods for basin and bedrock characterization, and when available, InSAR to document recent or current subsidence patterns.  Utilizing a synthesis of this information, subsidence modeling matching documented historic subsidence and estimating potential future subsidence can be developed to assess potential impacts on dam and levee infrastructure.

Utilizing the results of the site characterization and subsidence modeling, a finite-element stress-strain model can be developed to estimate past and future ground strain. Estimated tensional strain values can be utilized to predict where earth fissures are likely to initiate with future subsidence and reduce the risk of failure.

Multiple case studies from Central Arizona will be utilized as examples, including McMicken Dam and Powerline Flood Retarding Structure which are operated and maintained by the Flood Control District of Maricopa County, Arizona.

Thursday, July 17, 2014

About Me

This post serves as a basic introduction to who I am Professionally and Personally.

I am a member of the Association of Environmental & Engineering Geologists (AEG) and a registered professional geologist in Arizona. In September 2014 I become President of AEG. I am Senior Geologist with AMEC Environment & Infrastructure, Inc. (AMEC) in Phoenix, Arizona, though I reside in Flagstaff, Arizona. I have been with AMEC since November 2000. Since that time, I have been utilized as a project manager, technical lead, project geologist, task manager, and field geologist performing geologic, geotechnical and geologic hazard investigations for dams, levees, channels, basins, buildings, roadways, bridges, power plants, transmission lines, mining projects, pipelines, and other structures. In addition, I have been extensively involved in the characterization of land subsidence and subsidence-related hazards such as earth fissures and associated impacts for planning, design and remediation. I have also been involved in projects that utilize remote sensing technologies such as interferometric synthetic aperture radar (InSAR) as they apply to geologic and geotechnical characterization, including ground subsidence and earth fissuring and slope stability issues. Involvement in this wide-range of projects has included field investigation, logging and sampling of soils and rock, seismic and resistivity surveys, quality inspection, gravity surveys and analysis, geologic mapping, aerial photographic and remote sensing interpretation, background research, data analysis, report preparation, supervision of drill and other field crews, and overall task management. I have also utilized mountaineering techniques obtained in a specialized training course to map the geology, fracture patterns, and other concerns on canyon walls specifically applied to geotechnical characterization for bridge foundations and slope stability. I have experience investigating geologic hazards such as land subsidence, earth fissuring, landslides and seismic hazards and has received specialized training in the use of LiDAR and high resolution DEMs for landslides and slope stability. I have worked internationally in Canada, Mexico, Germany, Romania, the Czech Republic, and have supported other projects worldwide.

My experience with AEG: Vice Chair, Phoenix Chapter (2003 – 2007); Chair, Arizona Section (2007 – 2010); Website Committee (2008 – 2011); Website Committee Co-Chairperson (2010 – 2011); Governance Committee (2010 – 2011); AEG Secretary (2011 – 2012); AEG Treasurer (2012 – 2013); AEG Vice President/President-Elect (2013 – present). I also served on the planning committee for the 2011 Shlemon Conference in Tempe, Arizona and am on the planning committee for the 2014 Annual Meeting in Scottsdale, Arizona.

Education: 1998: BS, Engineering Geology, Texas A&M University, 2001: MS, Geology, Arizona State University.

I am also active with the Arizona Hydrological Society (AHS), The Arizona Land Subsidence Group, The Arizona Geological Survey Earth Fissure Advisory Group, and the Geotechnical Extreme Events Reconnaissance (GEER)

I am a proud husband and a father of 2. My son is 6 (7 in October) and my daughter is 3 (4 in November). My wife is a planetary geophysicist with the USGS and my children love all things fun - sports, dancing, music, and the outdoors. We spend as much time outdoors as possible - mostly hiking the mountains outside of Flagstaff, and enjoying the trip down to Sedona when there's too much snow on the ground. I'm also typical of many geologists I know in that I enjoy a good drink - fine craft beer, scotch, wine, etc.

Wednesday, July 16, 2014

Back From The Dead

I figure it's about time to resurrect this blog and develop a new purpose. At the moment I (Ken Fergason) am the Vice President/President-Elect of the Association of Environmental & Engineering Geologists (AEG) and I will become President at our Annual Meeting in September (It's in Scottsdale, AZ and it's going to be an awesome meeting). I am going to utilize this blog to document my experience as President. I don't know yet how active it will be and what exactly the content will be, but I'm envisioning discussions on my travels, meetings I attend, presentations I give, people I interact with and such. I also imagine there will doomsday travel stories and gratuitous photos from a conference I'll be attending in Italy. Anyway, I'm hoping it'll a lot of fun. So stay tuned as content ramps up over the next couple of months.


PS: Current info on the Arizona Section of AEG can be found here.

Friday, July 8, 2011

2011 Shlemon Specialty Conference

2011 Shlemon Specialty Conference

Opportunities for Alternative Energy Development in Arizona and the Southwest – Geologic/Hydrologic Considerations

Association of Environmental & Engineering Geologists


Arizona Land Subsidence Group

October 27-28, 2011

Embassy Suites – Tempe, AZ

Take advantage of this exciting opportunity to network and see presentations by experts in geology, geologic hazards, soils, foundation engineering, hydrology, and land use as applied to opportunities for alternative energy development in Arizona and the Southwest U.S. Invited talks by the Arizona State Geologist, Arizona Land Commissioner, and experts from both the public and private sectors will provide an excellent educational opportunity as well as the chance to meet and network with industry colleagues. Registration for the day-long technical conference is only $100/person and CEU’s will be available. Additionally, there is a follow-up day-long field trip led by industry and agency experts that will show examples geologic and hydrologic issues discussed in the technical presentations and visit a local alternative energy facility. The cost of the field trip is only $60/person. Sponsorship and Exhibiting opportunities are available. A conference rate of $129 per night is available at the Tempe Embassy Suites.

More information including registration forms is available at the conference website:


Additional questions and inquiries can be sent by email to info@azlandsubsidence.org

Monday, March 21, 2011

UA AEG Meeting March 24th 2011

University of Arizona
Association of Environmental and Engineering Geologists

Call and Nicholas, Inc.
International Geotechnical Consultants

Invites You to a Presentation by
Robert Pratt, PE on
Rock Mechanics and Slope Stability

Free Brooklyn Pizza and Soda
Provided by Call and Nicholas, Inc.

When- UA AEG Monthly Meeting, Thursday March 24th, 12:30pm
Where- Mines and Metallurgy Bldg, Room 225

UA AEG Meeting March 24th 2011

University of Arizona
Association of Environmental and Engineering Geologists

Call and Nicholas, Inc.
International Geotechnical Consultants

Invites You to a Presentation by
Robert Pratt, PE on
Rock Mechanics and Slope Stability

Free Brooklyn Pizza and Soda
Provided by Call and Nicholas, Inc.

When- UA AEG Monthly Meeting, Thursday March 24th, 12:30pm
Where- Mines and Metallurgy Bldg, Room 225

Tuesday, February 15, 2011

ASU GeoClub Meet and Greet

GeoClub’s Second Annual
Meet and Greet

Thursday, March 3, 2011
5:30-6:30 PM Reception
in Dietz Museum
6:30 PM Professional Introductions
PSF 166
7:00 PM Informal Discussion Groups
PSF 166

This is an opportunity for students to talk to
professionals and find out about summer opportunities.
These could include internships, scholarships, jobs and

There will be professionals from Hydrology, Environmental, Mining,
Engineering Geology, Geotechnical , Academia and more!
For a full list of professionals and a short biography, please look at the
GeoClub website at


Tuesday, February 8, 2011

AEG Meeting 2/10/11

We have another great AEG meeting planned for February! The meeting will be on held Thursday February 10, 2011 at Monti’s located at the SWC of Mill Ave and 1st Street in Tempe. We'll start off at 6:00pm with a hosted happy hour courtesy of Enviro-Drill Inc. Dinner will be at 7pm with the presentation starting shortly after dinner.

Our speaker is Bill Haneberg, PG, PhD, the current Jahn's lecturer. His presentation is titled "3-D Rock Slope Modeling and Virtual Discontinuity Mapping Using Digital Photogrammetry". Please see the attached flyer for more details.

Please RSVP by Monday February 7th if you will be joining us! Thank you and hope to see you at the meeting!

Tuesday, February 1, 2011

AEG-AHS Student Night 2011

Student Night 2011
For All Arizona Students and Professionals in Groundwater,
Environmental, & Engineering Geology
Geotechnical Engineering and Geological Engineering Fields
Hosted By: AEG and AHS
Tuesday, April 12, 2011
Student/Professional Meeting
Schedule of Events:
5:30-7:00 Career Fair and Mingling
7:00-7:45 Dinner
7:45- 8:45 Student Presentations
8:45-9:00 Award Presentations
Arizona State University in Tempe
Student Memorial Union
Cochise Room

Thursday, August 26, 2010

EWB Meeting

Engineers Without Borders (ASU Chapter) Meeting
Wednesday, September 1st
6:30 PM PSH 151
Arizona State University

For more information contact Armando Villareal avillar2@asu.edu