Please refer to: http://www.snopes.com/crime/warnings/triangle.asp
The first thing you must realize is that building codes in the United States, and especially in California, are significantly different from those in the Middle East or Mexico. Most buildings in the United States are wood frame or steel frame construction. In the Middle East, unreinforced masonry is the standard, especially in the poorer rural ares. Wood frame and unreinforced masonry react differently during prolonged shaking.
A typical wood frame home or apartment will "flex" during an earthquake. In severe shaking the structure will suffer exterior and cosmetic damage (broken plaster, cracks, fallen chimneys, etc), but the structure will by-in-large, withstand the shaking. I have seen a wood frame home that was located on the fault trace of a large quake, where vertical offset tilted the home. Although it was a total loss for insurance purposes, the frame structure remained intact.
Desks, tables, and the like are also structurally strong. They can hold many times their own weight. The most likely source of injury in an earthquakes is from broken glass and objects falling on the victims. By ducking and covering, especially under a desk (as a student would in class), or under a nearby table, will help protect a person from further injury. The chance of a collapse of a typical wood frame structure is so small, that your suggestions are of little consequence from a safety standpoint.
Door jambs are small, strong structures. They rarely have any direct relationship with a ceiling. Your statement that people in door jambs get killed when a building collapses is a non-sensical statement. If a building does collapse, one's location in the building is of little relationship to death. (This was proved by a study done by the State of California after the Northridge earthquake. Door jambs and bearing walls often buttressed the effects of a collapse of non-bearing walls.) The reason I do not suggest that people take "cover" in a door jamb is because of the swinging door and the injuries it might causes to fingers and faces. But if you are in one when a quake strikes, stay there and brace yourself as best as possible.
The suggestion to get away from a building during an earthquake is a killer! Cosmetic brickwork, roof tiles, chimneys, and other exterior structures pose a greater threat to someone running from a building, than do the interior fixtures.
The observations about the Nimitz freeway collapse and the lack of survivors in crushed automobiles is factually incorrect. First, there are few, if any other structures like the old double-decked Nimitz freeway. If someone took your suggestion of exiting their vehicle on a freeway during an earthquake, the likely result would be that they would be struck by another vehicle. That was about the stupidest thing I have ever read regarding earthquake safety.
Copp's suggestions are controversial and are not supported by any of the major emergency action agencies.
Hmm... most injuries do result from flying debris...
I just read that the epicenter of the 06 shake was near the Mendocino Humboldt line