Java was formed by only tectonic shifts.
Java . Formed mostly as the result of volcanic eruptions , Java is the 13th largest island in the world and the fifth largest in Indonesia . Sedimentary basins are regions of Earth of long-term subsidence creating accommodation space for infilling by sediments . The subsidence can result from a variety of causes that include : the thinning of underlying crust , sedimentary , volcanic , and tectonic loading , and changes in the thickness or density of adjacent lithosphere .