1 Inflammation of the gingiva, bone loss, and increased gingival recession may progress slower than with other forms of periodontitis.  Periodontitis Associated with Systemic Diseases - Systemic diseases, such as heart disease, diabetes, and certain forms of arthritis, may have a correlation with periodontitis.
Main Content. An earthquake is ground shaking caused by a sudden movement of rock in the earthâs crust. Such movements occur along faults, which are thin zones of crushed rock separating blocks of crust.
Earthquakes occur when the two sides of a fault slip suddenly against each other. The Pacific and North American plates move past each other about 1.5 inches a year. The friction between the plates causes stress, which is released when the blocks of crust slip suddenly along a fault plane.