Sunday, August 24, 2014

Northern California Earthquake - South Napa 6.1

At around 3:20 A.M. this morning, the Northern California area was shaken by one of the largest earthquakes since the late 90s. The USGS told ABC News that dozens of aftershocks followed, with one reaching 3.6 magnitude. Many thousands of people are without gas and electric service, per the Pacific Gas and Electric Company.

Queen of the Valley Medical Center in Napa has been receiving dozens of injured people from this event, minor injuries are so far numbered at 70. No deaths have been reported, but we do know of 2 MAJOR injuries in which those victims are said to be in critical condition.

"I've been through a few of these and I've never seen anything like this, particularly in downtown Napa," Dodd said, according to ABC News Radio. "The county building is just in total disrepair, and they've moved it down to the sheriff's office -- so that's where the coordinating all the emergency services for the county."

The fault that generated this quake has been dormant of activity for 1.6 MILLION years. The Earthquake Track website is reporting that there have been multiple earthquakes from northern to southern California over the last few days.

See these screen shots below detailing activity for the last 48 hours previous to today's event:

ABC Television News has this video: 

Watch more news videos | Latest from the US


Published on August 24, 2014 @ 10:38:55 UTC
Northern California Seismic System (NCSS) operated by UC Berkeley and USGS
Version 0: This report supersedes any earlier probability reports about this event.

Magnitude: 5.96 Mw (A strong quake)
Time: 24 Aug 2014 03:20:44 AM, PDT
24 Aug 2014 10:20:44 UTC
Coordinates : 38 deg. 12.85 min. N, 122 deg. 19.15 min. W 38.2142 N, 122.3192 W
Depth: 6.7 miles ( 10.8 km)
Quality: Excellent
Location: 4 mi. ( 6 km) NW of American Canyon, CA
8 mi. ( 13 km) NNW of Vallejo, CA
Event ID: NC 72282711

STRONG AFTERSHOCKS (Magnitude 5 and larger) - At this time (immediately after the mainshock) the probability of a strong and possibly damaging aftershock IN THE NEXT 7 DAYS is approximately 54 PERCENT

EARTHQUAKES LARGER THAN THE MAINSHOCK - Most likely, the recent mainshock will be the largest in the sequence. However, there is a small chance (APPROXIMATELY 5 TO 10 PERCENT) of an earthquake equal to or larger than this mainshock in the next 7 days.

WEAK AFTERSHOCKS (Magnitude 3 to 5) - In addition, approximately 30 to 70 SMALL AFTERSHOCKS are expected in the same 7-DAY PERIOD and may be felt locally.

This probability report is based on the statistics of aftershocks typical for California. This is not an exact prediction, but only a rough guide to expected aftershock activity. This probability report may be revised as more information becomes available.

Background Information About Aftershocks

Like most earthquakes, the recent earthquake is expected to be followed by numerous aftershocks. Aftershocks are additional earthquakes that occur after the mainshock and in the same geographic area. Usually, aftershocks are smaller than the mainshock, but occasionally an aftershock may be strong enough to be felt widely throughout the area and may cause additional damage, particularly to structures already weakened in the mainshock. As a rule of thumb, aftershocks of magnitude 5 and larger are considered potentially damaging.

Aftershocks are most common immediately after the mainshock; their average number per day decreases rapidly as time passes. Aftershocks are most likely to be felt in the first few days after the mainshock, but may be felt weeks, months, or even years afterwards. In general, the larger the mainshock, the longer its aftershocks will be felt.

Aftershocks tend to occur near the mainshock, but the exact geographic pattern of the aftershocks varies from earthquake to earthquake and is not predictable. The larger the mainshock, the larger the area of aftershocks. While there is no "hard" cutoff distance beyond which an earthquake is totally incapable of triggering an aftershock, the vast majority of aftershocks are located close to the mainshock. As a rule of thumb, a magnitude 6 mainshock may have aftershocks up to 10 to 20 miles away, while a magnitude 7 mainshock may have aftershocks as far as 30 to 50 miles away.

Northern California Earthquake Summary

Location and Magnitude contributed by: Northern California Seismic System, UC Berkeley and USGS Menlo Park

Event Time

2014-08-24 10:20:44 UTC
2014-08-24 03:20:44 UTC-07:00 at epicenter
2014-08-24 05:20:44 UTC-05:00 system time


38.215°N 122.318°W depth=10.7km (6.6mi)
Nearby Cities

6km (4mi) NW of American Canyon, California
9km (6mi) SSW of Napa, California
13km (8mi) NNW of Vallejo, California
14km (9mi) SE of Sonoma, California
82km (51mi) WSW of Sacramento, California

The earthquake is located between two major, largely strike-slip fault systems. The Hayward-Rodgers Creek Fault system, which is approximately 7 km (4 miles) west of the site, generated damaging earthquakes in 1868 and probably in 1898. The Concord-Green Valley Fault system, which is 12 km (7 miles) east of the site, produced a M5.5 earthquake in 1954; while it has not generated a large historical event, there is strong evidence for recent pre-historic activity. The 1999 Working Group on California Earthquake Probabilities (WG99, 1999) concluded that the Hayward-Rodgers Creek Fault system has a 32 percent probability of generating a large earthquake (M6.7 to 7.4) by the year 2030, and the Concord-Green Valley Fault system has a 6 percent chance of generating a large earthquake (M≥6.7) in the same time period.

The earthquake occurred near the north shore of San Pablo Bay. The bayshore areas in the San Francisco Bay region are underlain by landfill and bay mud and have experienced disproportionately greater damage during historic earthquakes. Such damage is caused by soil failure in the fills and amplification of ground shaking by the soft bay mud.

Incoming On-Scene facts:

Credible news sources, and those on the scene in the northern California historic district are saying that historic buildings have sustained significant to major damage in this morning's earthquake.

Rail Service Infrastructure: 

The Amtrak Capitol Corridor service has been shut-down between Roseville and San Jose' due to track inspections and to keep Amtrak passengers and personnel safe.

Evacuation  centers: 

Napa High School gym

Grace Church

Communications Infrastructure:

Communications instructions: DO NOT USE LANDLINES! Emergency agencies are stating that those in the area affected by this event should use other means of communications.

Amateur Radio Service Activity: None heard on the Win System, and no reports of amateur radio playing any role in this event at this time.

This coverage will be updated as more information is verified.