KUALA LUMPUR: The belief that Kuala Lumpur is situated on top of a large, hollow limestone cave is a myth.
Universiti Kebangsaan Malaysia engineering geology and soil mechanics expert Dr Nor Shahidah Mohd Nazer clarified that limestone formations were not present throughout Kuala Lumpur but confined to specific areas.
She also emphasised that sinkholes, such as the sinkhole incident which occurred in Jalan Masjid India on Aug 23, were not necessarily caused by the presence of limestone formations.
"Limestone is associated with karst morphology, which creates cavities or caves when the limestone dissolves in water. However, if we misinterpret the presence of such caves, it could lead to unnecessary panic, even though limestone formations are only located in certain areas. It is therefore incorrect to claim that there are extensive caves as suggested," she explained.
She acknowledged that while limestone is present and construction projects might uncover small-scale cavities, these are not extreme and can still be managed.
Nor Shahidah said this during the Berita Harian 'Borak Hari Ini,' podcast titled 'KL sits on limestone caves, fact or myth?' which also featured Malaysian Ecological Society president Prof Dr Ahmad Ismail.
On Saturday, the Natural Resources and Environmental Sustainability Ministry said investigations conducted by the relevant agencies found that the Jalan Masjid India sinkhole incident was caused by several factors, namely, human activities, weather and underground soil erosion.
https://www.nst.com.my/news/nation/2024/09/1102485/kl-sinkhole-human-act...
The statement said that generally, Kuala Lumpur is a safe place to live, adding that the city's bedrock (foundation) is made out of 30 per cent limestone and 70 per cent granite and metasedimentary rocks, namely the Kenny Hill Formation, Hawthornden Schist and Dinding Schist.
Dr Nor Shahidah said more detailed studies were required to ascertain if there is a large limestone cave beneath Kuala Lumpur, adding that even if there are limestone caves, the dissolution process caused by acidic water would take millions of years, and not a short period.
"In Malaysia, we have various types of rock aside from limestone, and the area also experiences soil movement issues.
"For example, Bukit Antarabangsa is not limestone-based (but has experienced landslides). Limestone is a weaker element compared to other rocks, hence the need for close observation due to human activities," she said.
Prof. Ahmad stressed the importance of relevant agencies providing more detailed and current data regarding the limestone pathways in the capital.
He acknowledged there was insufficient geological data about the capital and emphasised the need for closer cooperation between experts and government agencies.
This includes data on the impact of acidic rain due to air pollution on limestone in Kuala Lumpur.
"Why did the sinkhole occur on Jalan Masjid India and not elsewhere? We cannot know without data. We have technology to check the surface, but we need to monitor new technologies to obtain data about limestone formation pathways, for instance, from Batu Caves. Do we have data on all these pathways?
"With such data, we can address public concerns and provide explanations to alleviate their worries," he added.
He said cooperation from the relevant authorities is needed to provide funding for the experts to carry out the studies to produce this important data.