Iben Browning has incurred the wrath of geologists and seismologists for projecting a 50-50 chance for a major earthquake on the New Madrid Fault zone in early December.

He may soon be getting in trouble with economists.During a presentation Thursday to a St. Louis business group, the New Mexico scientist said it appears that conditions are right for the world to fall into a depression in 1992.

"For climatological reasons, we will reach the bottom of the depression about the end of 1992. . . . I expect will be the most severe since 1776, more severe than the 1930s," Browning said.

Among other things he said:

- That high tidal forces have affected such things as the size of the wheat crop in the Soviet Union and the rise of Nazism before World War II.

- That volcanoes cause acid rain, not coal-burning factories and power plants.

- That the temperature of ice in Greenland affects the world economy.

One thing he didn't spend much time talking about was his projection that strong tidal forces could touch off a major earthquake in the Midwest about Dec. 3. He also had nothing to say about the overwhelming criticism it has prompted.

Although he referred to his projection as a "guesstimate," he said he was confident in his reasoning and thought people should listen to what he has to say.