Earth Changes
No damages or injuries were reported, a Riverside County sheriff's dispatcher said.
Indonesian officials - who have been under fire for failing to warn people ahead of last week's deadly tsunami on Java island - recorded the quake at 6.6 and said it had the potential to trigger destructive waves.
They later said no tsunami was generated and told residents to return home.
The sweltering weather hit particularly hard in France, where the government issued warnings on radio and television after the number of reported deaths attributable to the heat reached 22.
The death toll raised memories of a fatal bout of baking temperatures that killed 15,000 people in France and more than twice as many across Europe in 2003.
Xinhua news agency said Saturday another 38,000 buildings were damaged by the quake measuring 5.1 on the Richter scale which shook Yanjin county in Yunnan province at 9:10 am (0110 GMT).
With temperatures topping 100 degrees this month in Denver and elsewhere along the populous Front Range, routine activities like filling up at the gas station or mowing the lawn are releasing fumes into a perfect cauldron for creating ozone, a major component of smog.
Activists are sounding the alarm. Government officials are keeping watch. Nobody's breathing easy.
A 32-year-old man died in Spain after suffering heatstroke while working on a farm in Caceres in the east, local health authorities said on Thursday. He was Spain's third heatwave victim after a builder died in Murcia in the south on Sunday and a 44-year-old man died on Tuesday in Galicia in the northwest.
Sixteen people have died so far across Europe, where thermometers have hovered over the 30 degrees Celsius mark (86 degrees Fahrenheit) for several days, but authorities in France said that measures implemented following the 2003 heatwave had averted another disaster.
The sisters, from the northern province of Phichit, were hospitalized after displaying symptoms similar to those seen in bird-flu sufferers, local health authorities told the Thai media.
Satellite images showed some 567 "hot spots" from fires and underground heat centres in Riau province on Sumatra as well as Kalimantan in Borneo, a spokesman from Indonesia's forestry ministry Masyud told AFP.
At least 476,000 customers lost power, Metrolink was shut down and just one-third of flights were getting in and out of Lambert Field.
"This is one of the worst storms we can all remember to hit the city of St. Louis in recent years," St. Louis Mayor Francis Slay said at a hurriedly called news conference.