For a natural agent as an earthquake, the sun (actor -um- & inst) to crack cement, soil, sheet rock, a rock (patient -on).
umnga'; engnga'; manga'; onga'on; mangnga'
Nan duntug ya engnga' din alyog hidin penghāna.
As for the mountain, an earthquake cracked it long ago.
manga' is most common form.
-um-: umnga'; ma-: manga'; -iɴ-: engnga'; -on: onga'on; maN-: mangnga'