Thanks for your insights, so it's basically down to the perilous evil of wrongly executed base-to-final turns. A student pilot on the 2nd x-country solo flight should be adequately trained for that.
I found the crash location about 2 miles from the threshold of runway 30. Assuming the flight was arriving from Van Nuys from SE direction, a straight-in to runway 30 would have made the circuit unnecessary. Something probably happened that the aircraft had to make the base-to-final turn, e.g., being vectored to the base or downwind leg, rather than a straight in, or a possible go-around.
https://www.google.com/maps/place/34...4d-120.4141845