COSTA MESA — What caused a 10-ton tree to fall on a woman's car while she waited at a stop light remained unclear to public safety officials and seismic and horticultural experts Friday.
But theories — from moist soil to trimmed roots to this week's earthquake — emerged from the tragedy that claimed Haeyoon Miller, 29, who died following the impact on 17th Street and Irvine Avenue on Thursday afternoon.
A 3.5 earthquake that took place off Newport Beach about 2:56 a.m. Thursday may have played a role, though there easily could have been other contributing factors, according to Lisa Grant Ludwig, a UC Irvine seismologist.
About 380 people in Costa Mesa reported feeling the earthquake on the U.S. Geological Survey site, according to Ludwig.
"[That's a] good indication right there that that location was shaken relatively strongly," she said. "It's possible."
But soil conditions, whether the ground was wet or slanted, and the health of the tree, are all potential factors that could have felled the 50-foot blue gum eucalyptus, she said.
The city of Newport Beach, which has a contract with the city of Costa Mesa to maintain the trees near the cities' shared borders, said in a statement that the city is investigating what felled the tree.
The tree showed no signs of illness, according to the city.
The trees on the meridian are inspected every six months and were last pruned in April, according to the satement.
Eucalyptus are known for shedding bark and branches, but are not known to topple, said Laura Lyons, nursery manager at the UC Irvine arboretum.
Lyons said the UCI arboretum took out their eucalyptus "in part because of the liability."
Miller, who was in her blue, 2002 Hyundai at a red light at the time of the tree's collapse died of accidental blunt-force trauma, according to Larry Esslinger, supervisor and deputy coroner at the Orange County coroner's office.
She was on her lunch break from her job as an executive assistant at a mortgage firm, DLJ Financial in Newport Beach, according to friends. The victim also ran a children's gym with her boyfriend.
At the time of the accident Miller may have been on her way to pick up a brochure featuring photos she took of a friend's children, said George Osorio, 58, her boyfriend of five years. The couple had been sending text messages earlier in the day.
Miller was from South Korea, but as a violin prodigy moved to the United States with her parents when she was about 10 to attend the Juilliard School in New York, Osorio said. She went onto to perform atCarnegie Hall.
She spent most of her high school years at San Clemente High School. She attended USC but did not graduate, Osorio said.
Osorio and Miller lived in their Tustin home together for about a year, and would take trips up the California coast, to Seattle and Oregon, to "just to see places that were interesting for photographs," he said.
The two met after Miller began adult gymnastic classes at the gym where Osorio taught in Aliso Viejo. Miller had always wanted to do gymnastics but wasn't allowed as a child.
After a divorce, she began taking classes.
In January her love for photography and gymnastics combined at Pix&Flips, a personalized fitness training program for children.
"I always kind of teased her with, 'Where you twirling around this weekend?'" said co-worker Glenn Toher, 40. "I always referred to Haeyoon as a jack-of-all trades. She was kind of like Morgan Freeman in 'Shawshank Redemption.' She knew how to do everything."
Miller was also an avid reader, and read dozens of books last month, according to Toher, but at Pix&Flips she showed people a different side.
"[She] really lit up when she was around kids," Toher said.
Miller is also remembered for her honesty and quiet grace.
"She had a reserved elegance," said Casey Turner, 38, who worked with Miller for seven years. "Nothing was ever above her. She was always calm, always collected. … She was amazing. She was everything to everybody. One of the most selfless people I've ever known in my life.
"[She was] the best kind of friend because she was unbelievably honest — she always made me reflect on the truth. She wasn't the kind of friend who would always agree with you and pump you up. She was honest. She'd tell you, 'You're out of line. You're wrong.'"
Even during the recent economic downturn, John Renfro, 52, remembers Miller taking care of friends, treating them to dinners, and remembering everyone's birthday.
Miller's family is scattered, with her father in South Korea, her sister in Finland and her mother somewhere in California, but Osorio wasn't sure exactly where.
She was previously married, but her former husband could not be reached by the Daily Pilot.
Residents said a tree in the same median fell about a year ago, but no one was injured in that incident.
On Friday, flowers were tied with yellow ribbons to an eucalyptus tree on the meridian where the giant tree fell onto Miller's car.
Potted plants filled the hole left by the eucalyptus, many with notes from residents near the accident.
Melissa Nesheim, an Orange Coast College student who lives about three blocks away from where the accident occurred, dropped off flowers to the site.
"I know what it's like to lose someone to an unfortunate accident," Nesheim said.
Some friends, though, saw the accident as possibly having a higher meaning.
"I guess God needed her," Toher said.