If you can demonstrate some chops in geophysics- not just the qualitative knowledge (though that is of course important) but fair comprehension of the component mathematics, you would be a candidate for a position as a technician in one of several types of consulting firms. The thing is, the vocation "geologist" actually has a statutory DEFINITION in most U.S. States, and, in the consulting racket anyway, a geologist-in-training, hired after graduation with a college degree, expects (and is expected by his employer) to eventually satisfy the conditions for State Licensure as a registered Professional Geologist (PG). These conditions are always a 4yr. Geosciences degree, usually around 5 years of work under another P.G., and successful completion of a Board examination (usually the ASBOG). Once, in some States, it was possible to obtain a PG (or a PE) without a degree, if you could pass the exam and demonstrate some lengthy period of equivalent work/training (10 + years?), but as far as I know, this is no longer the case anywhere. Before all States had a licensure program, plenty of cats without degrees (or qualifications) could and did call themselves by the title, but States have learned that geological work can have an immediate impact on the Public's well-being....there are legal ramifications to a geologist's work, as well as a lot of liability, and so, quite rightly, there must be standards.
To be fair though, a lot of geologists (especially in Environmental Consulting) find themselves engaged in work that ANY moderately-literate person with some reasoning capacity could perform. Sometimes to save money, firms do hire non-degreed personnel as "environmental specialists" or other more or less vague job-title....I've known several that were talented, clever individuals with lots of specific knowledge who were probably better at managing projects than many post-grad engineers or geologists I've known. BUT, these personnel can never become a PE or PG, so they can never bill out at the $120.00 an hour rates that the employer expects to eventually get from its senior people, nor can they do expert-witness stuff, certify drawings or plans, make certain decisions, or a host of other things. They soon discover this impenetrable barrier to upward mobility, while the employer gets away with paying them half of what they must pay a senior PG to keep him or her. This can foster quite a lot of bitterness, to be honest...but there it is. Becuase they occupy a sort of pseudo-professional status, expect the employer to put you on salary, which means no OT for a job that is NOT 8-5. Ever.
Techs for your average geotech firm do a lot of construction-related materials testing, like compaction-testing of structural backfill, Procter and soil density tests, concrete testing, maybe drill-crew work... The facts: the pay is fair for a job that requires only a h.s. diploma, the work is often outdoors and you have a lot of responsibility, it IS physically-demanding, the hours are long, sometimes in inclement weather, you work weekends, nights, you work construction-schedules, which are ALWAYS behind. A lot of smaller firms require YOU to have your own truck, which you will destroy in about 2 years. They do reimburse for mileage, and you usually get OT. These sorts of positions can, if you excel, grow into management positions that pay well, and a GOOD construction materials guy can be something of a commodity, and cats with experience and talent are a rarity. Run of the mill dirt techs are not. There are various certifications that are involved with this work- concrete testing, asphalt testing, steel/rebar evaluation, operation of nuclear density gauges- fair resume fodder, once accumulated.
These are the sort of jobs a non-grad can get that I am familiar enough with to offer anything on. Now there are also firms that do geophysical testing, ground-penetrating radar, geoprobe services and sampling, surveying, environmental remediation companies, waste disposal.drilling companies- these also hire HS graduates as technicians, but I am less familiar with conditions or what you might expect, so I'll abstain comment. There IS work out there...but HOW related you will consider it to be to "geology" is difficult to guess. These firms also have clerical, drafting, IT and marketing people- these are never scientists. The fact is, most graduate geologists find themselves in a job where they ask themselves daily, "What the ***** does this have to do with geology? Why did I go to school? " etc., ...but that's my internal cynic talking. .
And the consulting racket is just one employer of geologists... there's government, mining, petroleum, non-profits and advocacy, land development, industry, and no doubt all of these employ HS grads for work supporting whatever geology is being done.