Leona Kelly said there was now an air of "nervous apprehension to see if there is going to be any more aftershocks or tremors”.
Leona Kelly (31) was in a sports hall when the tremors began.
"The whole thing lasted about 30 seconds,” she said. “The sports hall that I was in was shaking significantly.
"There were kids starting to scream. It was just a little bit chaotic."
Ms Kelly said that there was "significant shaking of buildings" with high rise buildings "swaying".
"I think there was significant damage around the city," she said.
She also said there was now an air of "nervous apprehension to see if there is going to be any more aftershocks or tremors”.
Public transport had been suspended with "lots of people piling out onto the streets,” she added.
"At first, I was a little bit scared. I didn't really know what it was," she said.
"I felt a little bit lightheaded. Then I quickly realised what it was.
"The first thing I did do was text my family and let them know what had happened."
Leona Kelly
Leona Kelly
The Thai capital has declared a state of emergency as dozens of buildings are now in ruins and hundreds of people are missing.
A dramatic video circulated on social media this morning showed the multi-story building with a crane on top collapsing into a cloud of dust, while onlookers screamed and ran.
Police told The Associated Press they were responding to the scene near Bangkok’s popular Chatuchak Market, and had no immediate information on how many workers were on the site at the time of the collapse.
Thai Prime Minister Paetongtarn Shinawatra called an emergency meeting to assess the impact of the earthquake.
“All of a sudden the whole building began to move, immediately there was screaming and a lot of panic,” said Fraser Morton, a tourist from Scotland, who was in one of Bangkok’s many centres shopping for camera equipment.
“I just started walking calmly at first but then the building started really moving, yeah, a lot of screaming, a lot of panic, people running the wrong way down the escalators, lots of banging and crashing inside the mall.”
Like thousands of others in downtown Bangkok, Mr Morton sought refuge in Benjasiri Park, away from the tall buildings.
“I got outside and then looked up at the building and the whole building was moving, dust and debris, it was pretty intense,” he said. “Lots of chaos.”
The US Geological Survey and Germany’s GFZ centre for geosciences said the incident was at a shallow 6.2 miles, with an epicentre in neighbouring Myanmar, according to preliminary reports.
The greater Bangkok area is home to more than 17 million people, many of whom live in high-rise apartments.
Alarms went off in buildings as the earthquake hit around 1.30pm local time, and startled residents were evacuated down staircases of high-rise buildings and hotels in densely populated central Bangkok.
The epicentre of the earthquake was in central Myanmar, 30 miles east of the city of Monywa.
In the capital Naypyitaw, the earthquake damaged religious shrines, sending parts toppling to the ground, and some homes.
There were no immediate reports of the effect of the earthquake in Myanmar, which is in the middle of a civil war.
Thailand’s Department of Disaster Prevention said the earthquake was felt in almost all regions of the country.
One Dublin woman Julie Mehigan, Christian Aid’s Head of Asia, Middle East & Europe, said an "urgent emergency response" is needed with full humanitarian access.
“This disaster will has left people isolated, devastated and in need of drinking water, food and shelter," she said, according to the Irish Independent.
“Christian Aid has heard from partners and colleagues on the ground that the Kyaukse Kinta Dam has burst in Mandalay with water levels rising in the lowland areas around.
“We are working closely with our partners and networks to identify the extent of the existing damage and risk to communities there. Mandalay airport is closed to international and domestic travel due to damage to the infrastructure.
“Christian Aid is reaching out to our partners to carry out assessments to identify the most vulnerable people who need our help immediately. However, with a nationwide power outage, communication will continue to be challenging.
“Myanmar is one of the least developed countries in the world. Even before this heartbreaking earthquake, we know conflict and displacement has left countless people in real need. Every prayer and every gift will bring hope to people hit by disaster.”