Parkfield, uninc. town (2000 pop. 37), Monterey co., Calif., among rolling hills in the Coast Ranges. A mining center for mercury and coal in the early 1900s, when the town had 900 inhabitants, Parkfield is today best known as the "earthquake capital of the world." From 1857 to 1966 six magnitude 6 earthquakes occurred along the San Andreas fault near Parkfield. Because the earthquakes occurred at average intervals of 22 years, in the mid-1980s seismologists began setting up a number of different types of monitoring equipment in the local area in hopes of learning more about earthquakes and how to predict them. Since then, Parkfield has become the most intensively monitored seismological site in the world. The much anticipated seventh quake occurred later than expected on Sept. 28, 2004.