RESIDENTS STILL FEEL EMOTIONAL AFTERSHOCKS.

Byline: Deborah Sullivan Daily News Staff Writer

The images come rushing back unbidden to Yolanda Ruiz: the violent jolt from sleep, the scramble to grab her baby daughter and young son, the flood of water that surged down Balboa Boulevard here, and the explosive fireball that followed.

On Saturday, exactly four years to the day after the Northridge Earthquake shook her world apart, Ruiz said she still is feeling the emotional and financial aftershocks.

The family repaired their shattered home, although it took a $40,000 state loan to do it. And her baby girl is now a precocious 4-year-old who sings along with Selena songs.

Life has gone on for her and her family, as it has for many Los Angeles residents who trembled from the 6.8-magnitude quake at 4:31 a.m. Jan. 17, 1994.

But Ruiz, like thousands of other in Los Angeles, is haunted by memories of what she calls ``the darkest night of my life.''

Throughout the city, residents paused Saturday to recall the quake that killed 61 people, injured 9,000 and caused more than $40 billion in damage and economic losses.

In Santa Monica, nearly 200 patients and hospital workers brought together when the quake shattered St. John's Health Center and the hospital gathered again for what was dubbed ``A Celebration of Heroes Earthquake Reunion.''

More than 180 people attended an open house at California State University, Northridge's geological sciences department, which was held to show off quake repairs and renovations. Although the event coincided with the quake anniversary, among the maps, fossils and rocks on display were several charts highlighting quake-ravaged areas of the San Fernando Valley.

For Ruiz and her neighbors, the quake wasn't just one strike, but a series of disasters that started with the pistonlike shaking, then progressed to broken gas and water pipes and then to a fiery explosion. The blast occurred when gas from a broken line was ignited by a driver's attempts to start his stalled pickup truck.

``The whole neighborhood lit up, like it was daylight,'' Ruiz said. ``The flames were about 100 feet high.''

Ladawn Taylor, 13, recalls the flames streaking under her house and scorching a tree that still stands withered in front of it.

``I was afraid, shaking, crying,'' she said.

Another of Ruiz's neighbors, Buzz Carmen, 51, said she would like those memories to fade.

``I just try to forget it,'' she said. ``Hopefully I won't be there when the next one comes.''

Several empty lots overgrown with thick, green carpets of weeds are all that remain of several houses that burned in the explosion.

Daily News Staff Writer Sharline Chiang contributed to this story.