Abstract: A method for predicting jumps in pore pressure of a subsurface includes the steps of obtaining a porosity and a resistivity log value while drilling; dividing a cross plot of the porosity and the resistivity log values into two regions where the split of the two regions is based on the following (I): R=0.062/ø1.5; averaging the obtained porosity and resistivity log values in the subsurface within a set interval to obtain a representative value of resistivity and porosity for the subsurface within the set interval; and giving a first warning of a high overpressure region if the representative value of resistivity at the representative value of porosity is lower than 0.062/ø1.5. The method may also include giving a second warning that a jump in pore pressure is coming within 100-300 meters if the normalized values of resistivity and porosity has a turning down point in its trajectory.