I don't think the answer is well established but its present estimate is in between 6000 K to 7000 K.

Thank you Digvijah, I need the exact or nearly exact. I need this value to optimize seismic design for structures. Rather if the maximum is 7000 K, then I am on. In the past I used 6335K, but ther e are some limitations.

Hi Krishna, I am giving you a picture of the effects of the Earth's crust temperature: Note that most of the earthquake's energy is converted into heat generated by friction. In other words, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though the changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior.. Further more energy released in an earthquake, and thus its magnitude, is proportional to the area of the fault that ruptures and the stress would drop.