Tooj liab yog los ntawm cov kua dej thermal, feem ntau yog tsim los ntawm cov dej, thiab tso tawm los ntawm cov magma txias.Cov magma, uas tseem yog lub hauv paus ntawm kev tawg, los ntawm nruab nrab txheej ntawm lub ntiaj teb lub hauv paus thiab crust, uas yog, mantle, thiab ces nce mus rau lub ntiaj teb saum npoo los tsim ib lub magma chamber.Qhov tob ntawm chav no feem ntau yog nyob nruab nrab ntawm 5km thiab 15km.

Kev tsim ntawm tooj liab deposits yuav siv sij hawm kaum tawm txhiab mus rau pua pua txhiab xyoo, thiab volcanic eruptions yog ntau zaus.Kev tawg ua tsis tiav yog nyob ntawm kev sib xyaw ntawm ob peb qhov ntsuas tus nqi ntawm kev txhaj tshuaj magma, tus nqi ntawm qhov txias thiab qhov nyuaj ntawm lub pob zeb nyob ib puag ncig lub magma chamber.

Qhov kev tshawb pom ntawm qhov zoo sib xws ntawm cov volcanic eruptions loj thiab sediments yuav ua rau nws muaj peev xwm siv cov kev paub loj uas tau txais los ntawm volcanologists mus rau kev nkag siab tam sim no ntawm kev tsim cov porphyry sediments.