September 28, 2004
At 10:15 AM September 28 2004 Pacific time a moderate earthquake registering 6.0 on the moment magnitude scale struck the Parkfield area. This earthquake is important for several reasons. First, Parkfield sits atop the San Andreas Fault and an earthquake of this magnitude strikes about every 33 years. It has been quiet since 1966 and so has been overdue for a quake. Second, this area is the most measured ground in North America. The USGS has been monitoring this area for any movement since the 1980's. Below are the pictures That I took on September 28 in Parkfield showing various effects of the earthquake.
You can help the USGS determine the shake maps for this quake by filling out an online form regarding what you felt. Did You Feel It?
For more information recent earthquakes, visit the USGS web page. Recent Earthquakes in California and Nevada.
I have updated the pictures with ones taken on October 3, 2004. The fissures under the bridge follow the trace of the fault and have now been marked by the USGS. The fissures are diagonally across the fault as the west side moved north and pulled away from the east side. The fissures extend north and south of the bridge. Farther south along the Parkfield road, the road crosses the fault trace and the fissures show up as diagonal stripes. Note the pocketknife for scale.
Map showing the location of Parkfield
Picture of the Parkfield Bridge looking west in June 2004
Parkfield Bridge looking west on September 28, 2004
Parkfield Bridge looking west on October 3, 2004
Bridge looking west October 3 2004.
Bridge looking west October 3 2004
Gap on the bridge approach West end of bridge.
Closeup of Fissure in road
Closeup of Fissure in road
Cracks in ground under bridge
Cracks in ground under bridge
Cracks in ground under bridge
Cracks in ground under bridge
Cracks in pavement bridge approach
Cracks in pavement bridge approach
/Cracks in pavement bridge approach
Fissures in road south of parkfield
Diagonal fissures in road south of Parkfield
Fissure in field north of bridge
Fissure in field north of bridge
Fissure marked by USGS looking south
Fissure south of bridge
Fissure under bridge
Fissures in road south of Parkfield
Fissures in road south of Parkfield
Gap between the bridge and the road on the east side
Gap between the bridge and the road on the west side
Large fissure under bridge
Looking East June 2004
Looking East Sept. 28 2004
Looking east Sept 28 2004. Note the News crew setting up. The population of Parkfield went from a few people to hundreds within 4 hours of the quake.
Looking West June 2004
Looking west Sept 28.
Rocks dislodged by the quake
Rockslide
Sag pond with marked fissures trending across it
Gap between the bridge and the approach on the East side of Bridge
View looking north west from bridge along trend of fissures
View looking south east from bridge along trend of fissures
