USS Gridley (DLG-21) the "Spruance"-class destroyer to escort reflagged Kuwaiti oil tankers through the Strait of Hormuz during Operation Earnest Will. While homeward bound, transiting the South China Sea, "Gridley" rescued Vietnamese refugees sighted in a small boat off of the coast of Vietnam. A Vietnamese-speaking crewman aboard "Gridley" was able to translate for those rescued, facilitating the process. "Gridley" returned to San Diego in June 1989. On 17 October of that year, the ship's visit to Naval Station, Treasure Island, California, was interrupted by the 6.9 Loma Prieta earthquake that struck the San Francisco Bay area. "Gridley"s crew provided assistance to victims
Earthquake prediction location to only central California; the magnitude remained the same. A figure they presented had two more revisions, for M ≥ 7.0 quakes in central California. The five-year time window for one ended in July 1989, and so missed the Loma Prieta event; the second revision extended to 1990, and so included Loma Prieta. When discussing success or failure of prediction for the Loma Prieta earthquake, some scientists argue that it did not occur on the San Andreas fault (the focus of most of the forecasts), and involved dip-slip (vertical) movement rather than strike-slip (horizontal) movement, and so was not