cm (0.2 in) per year in the regions of concern. Extreme southern regions of the fault are creeping more quickly, perhaps sufficiently to prevent fault rupture there, but mostly the creep is insufficient to relieve the accumulating forces upon most of the fault and so will not prevent a large earthquake. The creep is sufficient to displace roads, curbs, and sidewalks and so visibly reveal the surface trace in many locations. Creep damage to asphalt road surfaces will usually appear as a series of echelon cracks. Creep effects may be seen also in older structures crossing the fault, some of which have been fitted with expansion joints to accommodate this slow motion. Earthquake shaking The magnitude of an earthquake, as indicated on a seismic scale, is roughly proportional to the length of the rupture, while the ground motion in the region surrounding the fault is highly dependent upon the local soil conditions, somewhat upon the distance and relationship to the progression of the fault rupture, and (as recently recognized in the 1989 Loma Prieta earthquake) reflected energy from deep discontinuities in the Earth's structure. The area affected by an earthquake is also dependent upon the density and uniformity of the soils surrounding the fault. *Recent examination of damage reports from the 1868 event suggest that the rupture over only portions of the Northern and Southern Hayward fault could generate a magnitude 7.0 event, far more powerful than either the 6.5 event shown here or the 6.7 previously recognized as a likely maximum. The terms used by ABAG for shaking intensity differ from the official descriptions of the Mercalli intensity scale, being somewhat softened (perhaps due to the extensive local experience with earthquakes), with terms such as "Rather Strong" becoming "Light", and "Ruinous" and "Disastrous" becoming variations of "Violent". Bayside soil conditions The Hayward fault is considered to be particularly dangerous due to the poor soil conditions in the alluvial plain that drops from the East Bay Hills to the eastern shoreline of San Francisco Bay. At the lower elevations near the bay the soil is mostly water saturated mud and sand, placed in the early 20th century as fill in marsh areas. This soil tends to amplify the effects of an earthquake and so producing significantly greater ground motion. Additionally, the soil itself can fail, turning into a liquid mud from the agitation, a mud unable to support buildings erected