Taiwan National Central University researchers have discovered that the many mud diapirs, or “mud volcanoes,” located on the seabed off Taiwan’s southwestern coast release methane gas during regular seabed pulsations caused by tidal movements.
If suitable methods can be developed to collect methane from the rich natural reserves of methane hydrate in these waters, it could become an important source of energy to help meet the country’s power needs, according to NCU earth sciences professor Hsu Shu-kun.
“There has been little prior research on the relationship between the ebb and flow of tides and the release of methane from the seabed,” Hsu said at a National Science Council news conference Oct. 26.
Hsu explained that in May researchers placed eight seismographs for 21 days near some of the approximately 100-meter-high mud volcanoes, in waters about 500 meters deep. Seismographic readings revealed the regular pulsations.
According to the team’s findings, water pressure near the seabed is reduced during low tide, leading to a release of methane into the water from the seabed’s methane hydrate—a solid compound in which a large amount of methane is trapped within a crystal structure of water.
During the periods near high tide and low tide, when water level changes and consequently water pressure changes are most pronounced, methane and carbon dioxide concentrations in the waters near the seabed around the mud volcanoes are more than 100 times regular levels, Hsu pointed out.
The diapirs are not actual volcanoes but instead formations created by geo-excreted gases and liquids, he noted.