An earthquake measuring 3.1 on Richter scale today hit tremor-stricken Harrat Al-Shaqa in the northern part of the Kingdom of Saudi Arabia. The area also witnessed a number of minor quakes of less than 3 points on Richter scale, the National Network station for Seismological Monitoring, an affiliate of the Saudi Geological Survey reported. In a statement, the authority confirmed that all changes in terms of thermal measures, radon gas and carbon dioxide condensations and ground fractures expansion are in stable rates.