Liquefaction can happen in silty sand, not just clean sand. A study used a shake table, chamber, and CPTu to test this. Results show that silty sand can liquefy, but fine particles don't create as much pore water pressure as expected. Liquefaction increases pore water pressure and weakens the soil. More shaking makes liquefaction start sooner. The amount of fine particles affects how quickly pore water pressure goes down after liquefaction. Silty sand can liquefy and take longer to recover due to its lower permeability.