Why does a glass rod become positively charged when it is rubbed with a silk cloth?

The core has positive charge, the electrons have negative charge. When you are rubbing the glass rod with the silk cloth, electrons are stripped away from the atoms in the glass and transferred to the silk cloth. This leaves the glass rod with more positive than negative charge, so you get a net positive charge.

Depending on how the continental plates move it can cause a continental scale shift.