Could releasing of geothermal energy from within the Earth's core cause a geological implosion of the Earth or in other words suck the surface of the Earth into its own core?
No. The Earth has been in the process of cooling for over 4.5 billion years. Use of some of that heat for a supply of geothermal energy is incredibly insignificant in that process.
Geothermal energy comes from the ground. Heat stored in the Earth is extracted to form geothermal energy. Heat is continuously generated deep below Earth's surface due to the convection currents in the mantle. This generation of heat will never stop heating fluids beneath Earth's surface, and so geothermal energy is very easily renewed.
It's not really a problem, per se, but the challenge with geothermal power is that it requires drilling to a geothermal heat source. Since drilling is expensive, geothermal power is most cost-effective in locations where geothermal heat sources are close to the surface and/or the ground is relatively easy to drill through.
A contact is a surface where one rock type meets a differing rock type. On a geological map, this is marked as a solid black line where the contact is confirmed by surface observations and so can be plotted accurately. If the presence of the contact is certain, but its exact location is uncertain it will be marked by a dashed black line. See the related link from the US Geological Survey.