Company lists · Data refreshed September 2026

Top 25 Seismic engineering staffing companies based in the United States

Name: Seismic engineering staffing companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 29, 2026 1,524 companies tracked

RevenueBase identified 1,524 seismic engineering staffing companies headquartered in the United States as of September 2026 and tracks 36,958 professional contacts across them, including 14,257 with verified work emails. Houston is the largest hub.

This list covers seismic engineering staffing companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 29, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review

1,524Companies

36,958Contacts tracked

14,257Verified emails

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The 25 largest seismic engineering staffing companies based in the United States

Ranked by team size

Top 25 of 1,524 seismic engineering staffing companies based in the United States, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to seismic engineering staffing companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Terracon	Partial evidence	Olathe, KS, United StatesHQ checked Sep 29, 2026	5,001-10,000	6,113 contacts →
	Partial evidence “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Source: RevenueBase Database · checked Sep 29, 2026
2	Construction Labor Contractors	Partial evidence	Round Rock, TX, United StatesHQ checked Sep 29, 2026	501-1,000	1,234 contacts →
	Partial evidence “Let us make construction staffing work for you.” Source: RevenueBase Database · checked Sep 29, 2026
3	TRS Staffing Solutions	Strong evidence	Greenville, United StatesHQ checked Sep 29, 2026	201-500	1,187 contacts →
	Strong evidence “TRS Staffing Solutions is a world leading engineering recruitment agency specialising in the recruitment and supply of professional, engineering, technical and field talent.” Source: RevenueBase Database · checked Sep 29, 2026
4	GZA Geoenvironmental, INC	Indirect evidence	Norwood, MA, United StatesHQ checked Sep 29, 2026	501-1,000	880 contacts →
	Indirect evidence “Founded in 1964 as a soils and foundations specialty consultant, GZA GeoEnvironmental, Inc.(GZA) has grown into a full-service company providing its clients with highly…” Source: RevenueBase Database · checked Sep 29, 2026
5	Schnabel Engineering	Indirect evidence	Glen Allen, VA, United StatesHQ checked Sep 29, 2026	501-1,000	707 contacts →
	Indirect evidence “Schnabel is a trusted partner in building the foundation for project success.” Source: RevenueBase Database · checked Sep 29, 2026
6	Volt Technical Resources	Indirect evidence	Orange, CA, United StatesHQ checked Sep 29, 2026	5,001-10,000	584 contacts →
	Indirect evidence “A Six Sigma Company ~61 years in the industry ~Nationwide 4 million+ candidate database ~Fortune Company ~Extensive E-Recruiting capabilities ~Reference and Employment check…” Source: RevenueBase Database · checked Sep 29, 2026
7	Raba Kistner, INC	Indirect evidence	San Antonio, TX, United StatesHQ checked Sep 29, 2026	501-1,000	582 contacts →
	Indirect evidence “Founded in 1968, Raba Kistner Inc.” Source: RevenueBase Database · checked Sep 29, 2026
8	Saexploration	Indirect evidence	Houston, TX, United StatesHQ checked Sep 29, 2026	201-500	521 contacts →
	Indirect evidence “SAExploration offers a full range of geophysical ground acquisition services from design, prospecting, drilling, recording and analysis of field quality, as well as mobilization…” Source: RevenueBase Database · checked Sep 29, 2026
9	Trillium Construction Services	Indirect evidence	Kalamazoo, MI, United StatesHQ checked Sep 29, 2026	201-500	494 contacts →
	Indirect evidence “Trillium Construction Services has over a quarter of a century of experience in the construction recruiting industry.” Source: RevenueBase Database · checked Sep 29, 2026
10	Geoengineers INC	Indirect evidence	Redmond, WA, United StatesHQ checked Sep 29, 2026	201-500	479 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026
11	Entegee	Partial evidence	Burlington, MA, United StatesHQ checked Sep 29, 2026	201-500	468 contacts →
	Partial evidence “For the last sixty years Entegee has provided Fortune 500 and other companies with highly qualified engineering and technical personnel.” Source: RevenueBase Database · checked Sep 29, 2026
12	Sterling Engineering	Strong evidence	Westchester, IL, United StatesHQ checked Sep 29, 2026	501-1,000	402 contacts →
	Strong evidence “Sterling is an award-winning professional engineering consulting and technical staffing company.” Source: RevenueBase Database · checked Sep 29, 2026
13	Ardaman & Associates	Indirect evidence	Orlando, FL, United StatesHQ checked Sep 29, 2026	201-500	311 contacts →
	Indirect evidence “Ardaman & Associates, Inc.” Source: RevenueBase Database · checked Sep 29, 2026
14	Hillis-Carnes Engineering Associates, INC	Partial evidence	Annapolis Junction, MD, United StatesHQ checked Sep 29, 2026	201-500	299 contacts →
	Partial evidence “Hillis-Carnes Engineering Associates, Inc.(HCEA) is a Mid-Atlantic based, multi-disciplined consulting engineering firm.” Source: RevenueBase Database · checked Sep 29, 2026
15	ENGEO	Indirect evidence	San Ramon, CA, United StatesHQ checked Sep 29, 2026	201-500	282 contacts →
	Indirect evidence “ENGEO Incorporated is an award-winning, employee-owned comprehensive provider of more than 400 geotechnical and civil engineers, geologists, GIS experts, environmental scientists…” Source: RevenueBase Database · checked Sep 29, 2026
16	Progressive	Partial evidence	Houston, TX, United StatesHQ checked Sep 29, 2026	51-200	262 contacts →
	Partial evidence “Progressive is a global staffing company connecting STEM talent with leading companies in the Power and Utilities, Renewable Energy, Oil and Gas, and Manufacturing industries.” Source: RevenueBase Database · checked Sep 29, 2026
17	CTS Complete Technical Services	Indirect evidence	Houston, TX, United StatesHQ checked Sep 29, 2026	51-200	250 contacts →
	Indirect evidence “CTS - Complete Technical Services, Inc.” Source: RevenueBase Database · checked Sep 29, 2026
18	Computers And Structures, INC	Partial evidence	Walnut Creek, CA, United StatesHQ checked Sep 29, 2026	51-200	218 contacts →
	Partial evidence “Founded in 1975, Computers and Structures, Inc.(CSI) is recognized globally as the pioneering leader in software tools for structural and earthquake engineering.” Source: RevenueBase Database · checked Sep 29, 2026
19	Geotek	Partial evidence	Las Vegas, NV, United StatesHQ checked Sep 29, 2026	201-500	215 contacts →
	Partial evidence “Incorporated in 1997, GeoTek is a full service consulting engineering firm specializing in geotechnical engineering, construction materials testing, special inspection, and…” Source: RevenueBase Database · checked Sep 29, 2026
20	Geocon	Partial evidence	San Diego, CA, United StatesHQ checked Sep 29, 2026	201-500	197 contacts →
	Partial evidence “Geocon is a California corporation established in 1971 as a professional engineering consulting firm providing comprehensive geotechnical engineering, geotechnical…” Source: RevenueBase Database · checked Sep 29, 2026
21	CTL Thompson	Partial evidence	Denver, CO, United StatesHQ checked Sep 29, 2026	201-500	189 contacts →
	Partial evidence “CTL\|Thompson (CTL\|T) has been providing innovative engineering solutions throughout Colorado since 1971.” Source: RevenueBase Database · checked Sep 29, 2026
22	Resource Options, INC	Partial evidence	Needham, MA, United StatesHQ checked Sep 29, 2026	n/a	187 contacts →
	Partial evidence “Resource Options Inc.(ROI) provides custom staffing solutions to the design, construction, environmental, & emergency response industries.” Source: RevenueBase Database · checked Sep 29, 2026
23	Integrated Talent Strategies ITS	Partial evidence	Holland, OH, United StatesHQ checked Sep 29, 2026	501-1,000	182 contacts →
	Partial evidence “ITS has been a leader in the engineering, technical and professional recruiting field since 1984.” Source: RevenueBase Database · checked Sep 29, 2026
24	United Consulting	Partial evidence	Norcross, GA, United StatesHQ checked Sep 29, 2026	51-200	176 contacts →
	Partial evidence “United Consulting is a multi-disciplined engineering consulting firm located in Norcross, Georgia.” Source: RevenueBase Database · checked Sep 29, 2026
25	SCI Engineering, INC	Partial evidence	St. Charles, MO, United StatesHQ checked Sep 29, 2026	51-200	174 contacts →
	Partial evidence “SCI Engineering, Inc.(SCI) is a nationwide, multi-discipline professional consulting engineering firm that provides comprehensive services across all phases of project development…” Source: RevenueBase Database · checked Sep 29, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: seismic engineering staffing companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names seismic engineering staffing companies.
Partial evidence: Its own public description names part of seismic engineering staffing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name seismic engineering staffing companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 1,524 seismic engineering staffing companies based in the United States

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Seismic engineering staffing companies based in the United States at a glance

As of Sep 29, 2026

38.6%Verified-email coverage

24.3Average contacts per company

1-10Median size (employees)

3.5%Largest-city concentration · Houston

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

778

11-50

484

51-200

193

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 1,524 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among seismic engineering staffing companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in the United States whose own description of what they do matches “seismic engineering staffing companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names seismic engineering staffing companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among seismic engineering staffing companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 14,257 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 29, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Seismic engineering staffing companies by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names seismic engineering staffing companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many seismic engineering staffing companies are there based in the United States?

RevenueBase identified 1,524 seismic engineering staffing companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Terracon, headquartered in Olathe, tops this list with the largest team on record.

Which city has the most seismic engineering staffing companies?

Houston leads with 53 headquartered companies, followed by New York (28) and San Francisco (24).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 14,257 verified decision-maker contacts tracked across these 1,524 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 29, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.