Around 12 people were still missing today after the 6.2-magnitude earthquake struck China’s northwestern Gansu province late Monday night, while netizens were intrigued by the speed with which rescue operations were completed.

Chinese media reported that search and rescue operations in Gansu were completed at 15:00 (09:00 GMT) on Tuesday, about 15 hours after the earthquake hit the remote and mountainous area near the border between Gansu and Qinghai provinces. At this time it is not clear whether the investigations in Qinghai are continuing.

In Gansu, 115 people had been found dead by 09:00 local time (03:00 Greek time) yesterday, Wednesday, while the injured numbered 784, according to the authorities.

Gansu has not reported any missing persons.

In neighboring Qinghai the death toll stood at 22while the injured numbered 198 and 12 people were missing as of last night at 20:56 local time.

Over 207,000 homes were destroyed and nearly 15,000 collapsed in Gansu, affecting over 145,000 people.

Online discussions have seen netizens focus on how quickly rescue efforts in Gansu were completed, with many suggesting that the sub-zero temperatures were the main factor in shortening the “golden period” for finding survivors — usually 72 hours after the earthquake.

People trapped in the rubble and exposed to prolonged temperatures of -10 degrees Celsius are at risk of rapid hypothermia and may only be able to survive for five to 10 hours, even if uninjured, local media reported, citing rescuers.

“They would have died by the time they were found, even 24 hours is already too long. The outside temperatures are below -10 degrees Celsius,” commented a user on the Weibo platform.

Other Weibo users cited other factors, such as the area to be searched was not particularly wide and everyone has been recorded in it, which led to the rescue operations ending in less than a day.