![]() Between 39 to 73 such events are expected in the next week. The chance of aftershocks strong enough to feel near the epicenter - magnitude 3 or greater - is virtually certain at more than 99%. The odds of a subsequent large earthquake continue to drop. During the week starting July 11, the USGS forecasts a 1 in 200 chance of a magnitude 7 or larger aftershock and a 43% chance of a potentially damaging magnitude 5 or larger aftershock. So far, all of the magnitude 4 and above aftershocks are occurring within the original aftershock zone. Aftershocks like this are normal, and in the coming days, seismologists expect additional magnitude 4 or larger aftershocks. Pacific Time a moderate magnitude 4.9 aftershock occurred near Ridgecrest. The blue dots are the events associated with the magnitude 6.4 and the red dots are associated with the magnitude 7.1 (USGS animation background image copyright Google Earth Used with Permission) This video shows earthquakes from a few hours before the July 4 magnitude 6.4 event through noon on July 8, 2019. Sources/Usage: Some content may have restrictions. Rarely is the surface rupture for large earthquakes expressed as a single, clear break, and in this case the rupture along part of its length is unusually broadly distributed. Their observations show that the magnitude 7.1 event caused a maximum of 6 to10 feet of right-lateral offset along about 30 miles of rupture. Field teams in the Ridgecrest area and on the Naval Air Weapons Station China Lake are documenting fault offsets through direct measurements using tools ranging from tape measures to mobile laser scanning. The earthquakes were large enough that the fault rupture reached the earth’s surface. Measuring Surface Ruptures and Fault Offsets Circles indicate where scientists have visited the fault surface rupture. (Credit: USGS. Ruptures from the magnitude 6.4 event are shown in black and blue, and ruptures from the magnitude 7.1 event are shown in red and green. General surface rupture based on field mapping and satellite data as of July 11, 2019. These locally installed instruments provide more precise measurements of small aftershocks, ground shaking, and ground deformation than more remote regional instruments can. ![]() Additional monitoring equipment will continue to be deployed to learn about this large earthquake. Some of this information helps us refine the USGS National Seismic Hazards Model, a series of maps that reflect what we know about where shaking is likely to occur over decades - information that is used to develop building codes and design structures to withstand the expected shaking.Īs of July 11, scientists from USGS, UC Riverside, and the Scripps Institution of Oceanography have deployed temporary equipment including at least 14 seismic and 13 GPS stations as well as five USGS nodal arrays. The data collected and knowledge gained will help scientists identify which faults broke during the earthquake, determine the extent of faulting and surface displacement, and locate areas of ground failure to better understand the earthquake and its aftershocks. This includes conducting aerial and ground reconnaissance of the extensive surface rupture, deploying temporary seismic and geodetic stations to record aftershocks, and coordinating efforts with military, state, local and academic partners. Ruptures from the July 5 magnitude 7.1 event appear in red.(Credit: USGS. Preliminary mapping of surface ruptures from the July 4 magnitude 6.4 event is shown in black. Seismic stations are indicated by triangles and GPS stations are shown as squares. Seismic instruments and GPS deployments as of July 11, 2019. Scientists from the USGS and other organizations continue field work and analyses to learn more about the series of earthquakes and aftershocks centered in the Southern California desert near Ridgecrest. Updated on July 12. Visit the USGS earthquake event page for more information. This forecast takes into account the behavior of past sequences in similar tectonic environments and the aftershock sequence observed for this event so far. The chance of a magnitude 3 or higher earthquake is 99% during the next week. The odds of a subsequent large earthquake continue to drop with time since the mainshock. As of July 18, there is a 1 in 300 chance of a magnitude 7 or greater aftershock, a 3% chance of a magnitude 6 or greater aftershock and a 29% chance of a magnitude 5 aftershock in the next week. Ruptures from the magnitude 6.4 event trend northeast to southwest, and ruptures from the magnitude 7.1 event trend northwest to southeast. General surface rupture based on field mapping and satellite data as of July 15, 2019.
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