AFTER SHOCKS/NEAR ESCAPES

AFTER SHOCKS/NEAR ESCAPES Stephen Dobyns (Viking, $19.95) For all its intelligence and wit, Stephen Dobyns' novel about the massive 1960 Chilean earthquake is easier to admire than to enjoy. The prolific Dobyns-an accomplished poet as well as the author of a justly praised series of detective novels set in Saratoga Springs, N.Y.-strains mightily to turn the disaster into a metaphor for the arbitrariness of fate and the fickleness of human memory. Unfortunately, the effort shows, making the novel far too didactic to carry much conviction as fiction. As a poet, one of Dobyns' strong points is his edgy treatment of nature, that two-faced inspiration of so much sentimental verse. Here, however, not a raindrop falls but that it exhibits Thematic Significance: ''The rain came as a blessing,'' we're told, ''because it helped put out the fires still burning in town. Although in Puerto Montt, as we learned later, it caused a terrible mud slide and many people were killed.'' A couple of hundred pages of being nudged in the ribs like that, and most readers will want to seek the comfort of a Dobyns detective novel, where overt rather than covert philosophizing is part of the fun. B -GL