But scientists have not ruled out blasting as a cause for the country-wide quake last week as the Council for Geoscience investigates further.
Presentations on earthquake readiness and slum settlement solutions at a global architecture congress have highlighted contributions to human dignity.
The Orkney earthquake with tremors felt as far away as Botswana and Mozambique was the largest magnitude quake in the past decade at an official 5.5.
Nicaragua has been hit by a 6.6 magnitude strong earthquake, the second in as many days.
There have been no reports of damage or injuries after a magnitude four tremor, which has been described as "quite a big guy", hit Johannesburg.
The death toll following an earthquake in Philippines has risen to 85, police have said.
China's worst earthquake in three years has killed at least 157 people and injured more than 5 700, the Ministry of Civil Affairs said.
Pakistani troops have scrambled to aid the remote victims of an earthquake centred in nearby Iran, as a strong aftershock has jolted the region.
A powerful 8.0 magnitude earthquake has set off a tsunami that has killed at least five people in a remote part of the Solomon Islands.
A minor earthquake in Swaziland has resulted in earth tremors being felt in parts of KwaZulu-Natal and Mpumalanga, East Coast Radio has reported.
A strong 6.6-magnitude earthquake has struck the Santa Cruz islands, part of the Pacific's Solomons group -- but there is no threat of a tsunami.
An earthquake measuring 6.5 has struck Mexico and officials have reported two deaths so far, including an 11-year-old boy.
Over 260 people are dead with the casualty count set to rise after a quake brought ruin to parts of Turkey, destroying homes and injuring thousands.
An earthquake of 7.3 magnitude hit eastern Turkey on Sunday, leaving dozens of people injured after several buildings collapsed.
A powerful 6.9-magnitude earthquake rocked north eastern India on Sunday, killing as many as eight people including five who died in tremors in Nepal.
New Zealand's quake death toll was confirmed at 71 with more bodies still to be recovered, but it was not known how many people might still be trapped
There was still no information available by Wednesday on how many South Africans were affected by Monday's earthquake in Christchurch, New Zealand.
A strong earthquake killed at least 65 people in New Zealand's second-biggest city, Christchurch, with more casualties expected.