Engineering trust from the ground up

Reliable insights that lead to stronger, safer outcomes.

our History

S.E. Medall Geotechnical Engineering office with vintage cars and orchard trees in background.

Four geologists wearing helmets and jackets examining and collecting rock samples on a rocky terrain under a cloudy sky.

Man wearing a hard hat and plaid shirt kneeling on rocky ground, hammering a stake into the soil at sunset.

Four geologists in hard hats examining rock samples outdoors on rocky ground at sunset.

Construction workers in safety vests and helmets conducting soil or pavement testing outdoors with equipment on a sunny day.

1973

where it all began

Our roots trace back to the founding of S. E. Medall & Associates, Inc., where a commitment to high-quality consulting first took shape.

1979

A partnership built on excellence

Luis Fernando Aragon joined as a partner, strengthening the company’s technical capabilities and expanding its presence throughout Southern California.

1980s–2000s

Expertise through every challenge

Through decades of consulting, evolving codes, and economic cycles, the firm continued to grow by prioritizing uncompromising quality, safety, and client needs.  We expanded services in geotechnical engineering, geology, laboratory testing, and special inspections — supporting both public and private development.

2009

A new name, same mission

The company became Aragon Geotechnical, Inc. (AGI), continuing its legacy under the second-generation leadership of C. Fernando Aragon. Our Riverside headquarters and full-service laboratory enable us to provide integrated engineering and testing solutions with faster response and tailored support.

Today

Strength for the next era of California

We are a certified SBE firm, trusted across transportation, community infrastructure, commercial development, and energy sectors.
Our team brings decades of combined expertise in: geotechnical and earthquake engineering, engineering geology and hydrogeology,  pavement design and testing, concrete and steel inspections, nondestructive testing. We continuously invest in training and technology, because strong foundations aren’t built once; they’re built every day.

R.C.E., G.E.

C. Fernando Aragón

P.G., C.E.G.

Mark G. Doerschlag

P.G., C.E.G.

Mark G. Doerschlag

R.C.E., G.E.

C. Fernando Aragón

OUR HISTORY

Four construction workers wearing hard hats examining soil samples on rocky ground.

1973

where it all began

Our roots trace back to the founding of S. E. Medall & Associates, Inc., where a commitment to high-quality consulting first took shape.

our team

We are a multidisciplinary team of engineers, geologists, inspectors, and field specialists with decades of combined experience across Southern California. United by precision, safety, and innovation, we bring technical excellence to every stage of the project—from the ground up.

R.C.E., G.E.

C. Fernando Aragón

Learn more

OUR HISTORY

Building with vintage cars parked outside and a sign reading S.E. Medall Geotechnical Engineering Est. 1973

1973

where it all began

Our roots trace back to the founding of S. E. Medall & Associates, Inc., where a commitment to high-quality consulting first took shape.

OUR HISTORY

1979

A partnership built on excellence

Luis Fernando Aragon joined as a partner, strengthening the company’s technical capabilities and expanding its presence throughout Southern California.

OUR HISTORY

Man wearing a hard hat and plaid shirt kneeling on rocky ground while hammering a stake into the soil at sunset.

1980s–2000s

Expertise through every challenge

Through decades of consulting, evolving codes, and economic cycles, the firm continued to grow by prioritizing uncompromising quality, safety, and client needs. 

We expanded services in geotechnical engineering, geology, laboratory testing, and special inspections — supporting both public and private development.

OUR HISTORY

Aerial view of a modern industrial building with parking lot and construction equipment nearby on a dirt lot.

2009

A new name,same mission

The company became Aragon Geotechnical, Inc. (AGI), continuing its legacy under second-generation leadership. 

Our Riverside headquarters and full-service laboratory enable us to provide integrated engineering and testing solutions with faster response and tailored support.

OUR HISTORY

Five construction workers wearing helmets and safety vests inspecting asphalt pavement, with two measuring tools on the ground.

Today

Strength for the next era of California

We are a certified SBE firm, trusted across transportation, community infrastructure, commercial development, and energy sectors.Our team brings decades of combined expertise in: geotechnical & earthquake engineering, engineering geology & hydrogeology,  pavement design & testing, concrete and steel inspections, nondestructive testing. We continuously invest in training and technology, because strong foundations aren’t built once; they’re built every day.

our team

We are a multidisciplinary team of engineers, geologists, inspectors, and field specialists with decades of combined experience across Southern California. United by precision, safety, and innovation, we bring technical excellence to every stage of the project—from the ground up.

R.C.E., G.E.

C. Fernando Aragón

Learn more

R.C.E., G.E.

C. Fernando Aragón

Learn more

P.G., C.E.G.

Mark G. Doerschlag

Learn more

Map of California showing its counties outlined and labeled in muted brown color.

View of an ornate historic building framed by modern skyscrapers in a cityscape during daylight.

office information

16801 Van Buren Boulevard

Strategically located to serve Southern California

Our headquarters and full-service laboratory are based in Riverside, giving us direct access to major infrastructure corridors across Southern California. From coastal developments to inland public works, we mobilize rapidly—bringing field expertise, testing capabilities, and local knowledge wherever each project demands it.

Map of California showing major cities such as San Francisco, Los Angeles, San Diego, and Sacramento with a brown color scheme.

View of a historic brown stone building framed by modern skyscrapers in a city.

office information

3891 Ranchview Dr. Richardson, California 62639

(229) 555-0109

We’re ready to help

Contact our team

Request a Proposal

R.C.E., G.E.

C. Fernando Aragón

Civil & Geotechnical Engineer leading AGI’s second generation with broad expertise from soil mechanics to earthquake and pavement engineering. Focused on reliable, innovative, and cost-effective solutions.

R.C.E., G.E.

C. Fernando Aragón

Fernando specializes in solving complex subsurface and pavement challenges with a focus on performance, constructability, and long-term value. His expertise includes slope stability, settlement, and liquefaction analyses, as well as bearing capacity evaluations and comprehensive geotechnical investigations. He is also highly experienced in pavement engineering, including structural section design, distressed pavement rehabilitation, and advanced asphalt mix design, including both hot mix and cold recycled systems.

P.G., C.E.G.

Mark G. Doerschlag

Mark has played a key role in high-profile geo-engineering projects, includinginvestigations for two of the three dams at Diamond Valley Reservoir in RiversideCounty, as well as large-diameter tunnels in both hard and soft rock, deep shafts,and pipeline systems. His work is grounded in a deep understanding of geologicrisk and constructability across challenging environments.His technical expertise includes seismic hazard analysis, liquefaction evaluation,fault investigation, geomorphology, applied geophysics, and rock massclassification for underground construction. He also has extensive experienceevaluating sites affected by hydrocollapse and other complex geologic conditions.

R.C.E., G.E.

C. Fernando Aragón

C. Fernando Aragon is a Registered Civil and Geotechnical Engineer in California with over 20 years of experience delivering practical, high- performance solutions in geotechnical and materials engineering. He brings a full-project perspective—guiding clients from initial investigation and design through construction, testing, and final delivery.

Fernando specializes in solving complex subsurface and pavement challenges with a focus on performance, constructability, and long-term value. His expertise includes slope stability, settlement, and liquefaction analyses, as well as bearing capacity evaluations and comprehensive geotechnical investigations. He is also highly experienced in pavement engineering, including structural section design, distressed pavement rehabilitation, and advanced asphalt mix design, including both hot mix and cold recycled systems.

Known for his hands-on approach, Fernando plays a key role in construction-phase services, including inspection, materials testing, and quality control/quality assurance—ensuring that design intent is carried through to successful execution in the field.

He holds a Bachelor of Science in Civil Engineering from Loyola Marymount University and a Master’s degree in GeoEngineering from the University of California, Berkeley. He also serves as a subcommittee member for the Caltrans CIR/CCPR Committee, contributing to the advancement of sustainable pavement technologies.

Outside of work, Fernando enjoys spending time with his family, golfing, and traveling.

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P.G., C.E.G.

Mark G. Doerschlag

Mark Doerschlag is a Registered Geologist and Certified Engineering Geologist in California with over 35 years of experience in engineering geology. He leadsthe design, management, and execution of complex site characterizationinvestigations for a wide range of projects, including residential and commercialdevelopments, schools, hospitals, mining operations, and major infrastructurethroughout California and Nevada.

Mark has played a key role in high-profile geo-engineering projects, includinginvestigations for two of the three dams at Diamond Valley Reservoir in RiversideCounty, as well as large-diameter tunnels in both hard and soft rock, deep shafts,and pipeline systems. His work is grounded in a deep understanding of geologicrisk and constructability across challenging environments.His technical expertise includes seismic hazard analysis, liquefaction evaluation,fault investigation, geomorphology, applied geophysics, and rock massclassification for underground construction. He also has extensive experienceevaluating sites affected by hydrocollapse and other complex geologic conditions.

Mark earned his Bachelor of Arts in Geology from the University of California,Berkeley. He is an officer of the Inland Empire Chapter of the Association ofEngineering and Environmental Geologists and regularly serves as a subjectmatter expert for the California Board of Professional Engineers, Land Surveyors,and Geologists.

Outside of work, Mark enjoys exploring the mountains and deserts of Californiaand is an avid world traveler, often leading family and friends on adventures throughout Latin America, the Far East, and Australia.

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