“While I commend our students for drawing attention to a very real problem,” she said in a statement, “I am extremely disappointed that some graduate students chose to do so in a way that was unsanctioned by their union and is harmful to our undergraduate students, many of whom are struggling themselves.”

The strike is the result of long building frustrations.

Housing costs have made academic careers increasingly untenable in a state whose public universities are its crown jewels, its economic engines and most highly touted vehicles for upward mobility.

Graduate students I talked with described a kind of Catch 22: They are often recruited for their potential contributions to the work of a top-tier research university. A half-time job working as a teaching assistant is supposed to subsidize their study, so graduate student employees are discouraged from getting additional jobs.

The problem is that while graduate students’ overall compensation includes tuition remission and some other benefits, like health care, students say that the money they take home to use for rent ends up being more in line with a 20-hour-per-week job than a full-time position.

Ms. Hamilton, for example, estimated that she makes about $2,100 per month.

And in a place like Santa Cruz, which is well within a long-but-not-outrageous commute to Silicon Valley, that doesn’t go far.

[Read more about who got into the University of California last year.]

Ms. Hamilton and her husband’s rent is $1,900 per month — and she said she was set to move to a place that’s half the size. They’ll still be paying $1,800 each month.

Santa Cruz, students say, is an unaffordable market, which is why they started the unauthorized strike.