What is subsidence, heave, and landslip?

What is subsidence, heave and landslip are three types of ground movement that cause damage to buildings and land, important for insurance and construction. Subsidence is downward movement of ground, where ground sinks due to removal of support, such as clay shrinkage during drought, groundwater extraction, mining, leaking drains washing away soil, or tree roots drying soil, causing building foundations to drop and crack walls, with movement 5mm to 50mm, common in UK and Australia on clay soils. Heave is upward movement of ground, opposite of subsidence, where ground swells due to clay expansion when wet after tree removal or after long drought followed by rain, or frost heave in cold climates, causing floors and foundations to lift and crack, with similar damage but upward. Landslip, also called landslide, is sideways movement of ground down slope due to gravity, heavy rain, erosion or excavation, where mass of soil and rock slides down hill, damaging houses on slopes, common in hilly areas like Blue Mountains and Wollongong, causing major damage. For insurance, subsidence and heave often excluded unless sudden, landslip may be covered if not gradual. So subsidence is ground sinking down, heave is ground swelling up, landslip is ground sliding sideways down slope, all causing structural damage and need geotechnical investigation and underpinning or retaining walls to fix.