Global Volcanism Program | Shasta (2024)


Information is preliminary and subject to change. All times are local (unless otherwise noted)


July 1978 (SEAN 03:07) Cite this Report

Earthquake swarm; maximum M 4.2

An earthquake swarm in the vicinity of Mt. Shasta began at 0202 on 1 August. The first event, M 4.2, was followed by six M 3-4 events in the next 45 minutes. Between 35 and 40 shocks (M greater than or equal to 2) were recorded on 1 August. The number of events declined slightly the next day and only about ten had been recorded by midday on 3 August. About 20 of the total had M greater than or equal to 3. Permanent seismographs were too distant for precise hypocenter determinations, but USGS personnel were bringing portable seismographs into the area.

An ash eruption, probably from Shasta, was sighted from a ship off the California coast in 1786.

Information Contacts: R. Lester, USGS, Menlo Park, CA.


August 1978 (SEAN 03:08) Cite this Report

Earthquakes decline to few a day

The number of earthquakes declined to only a few events per day (M greater than or equal to 2) by 11 August. However, on 12 August a M 4.3-4.5 shock was followed by several similar events (approximately M 4), and others in the M 3.5-4 range occurred on the 13th. Activity then declined again; on 23 August only 13 events of M 2-2.5 were recorded, and by the end of August only about six events greater than M 2 were being recorded daily.

Epicenters have been located along about 2 km of a pre-existing N-S-trending fault zone 28 km E of the summit. Uncertain crustal velocities for the area have made depth determinations difficult, but all events have been shallow, probably less than 5 km, and some may have been less that 1 km deep. No migration of events has been observed. New tensional fissures have been found in the epicentral area, but were not growing as of late August. Leveling, microearthquake studies, and gravity profiles are planned.

Information Contacts: R. Sherburne, California Division of Mines & Geology; A. Walter, USGS, Menlo Park, CA.


September 1978 (SEAN 03:09) Cite this Report

Daily seismcity declines; no evidence of volcanic activity

Seismic activity E of Mt. Shasta had declined by late September to about six locatable events per day, most stronger than M 2. Hypocenters extended E from surface fissures 28 km E of Shasta, along a pre-existing N-S-trending fault zone. Focal depths were very shallow near the surface fissures, but increased to 4-6 km along an inclined seismic zone dipping 35-45° E. The events have not been migrating, nor has there been any evidence of volcanic activity associated with the swarm.

Further Reference. Bennett, J.H., et al., 1979, Stephens Pass earthquakes, Mount Shasta—August 1978; California Geology, February, 1979, p. 27-33.

Information Contacts: R. Sherburne, California Division of Mines & Geology.


June 1992 (BGVN 17:06) Cite this Report

No seismicity triggered by M 7.5 earthquake hundreds of kilometers away

Southern California's largest earthquake since 1952, M 7.5 on 28 June, appeared to trigger seismicity at several volcanic centers in California. It was centered roughly 200 km E of Los Angeles. In the following, David Hill describes post-earthquake activity at Long Valley caldera, and Stephen Walter discusses the USGS's seismic network, and the changes it detected at Lassen, Shasta, Medicine Lake, and the Geysers.

In recent years, the USGS northern California seismic network has relied upon Real-Time Processors (RTPs) to detect, record, and locate earthquakes. However, a film recorder (develocorder) collects data from 18 stations in volcanic areas, primarily to detect long-period earthquakes missed by RTPs. The film recorders proved useful in counting the post-M 7.5 earthquakes, most of which were too small to trigger the RTPs.

The film record was scanned for the 24 hours after the M 7.5 earthquake, noting the average coda duration for each identified event. Some events may have been missed because of seismogram saturation by the M 7.5 earthquake. Marked increases in microseismicity were observed at Lassen Peak, Medicine Lake caldera, and the Geysers (table 1). No earthquakes were observed at Shasta, but the lack of operating stations on the volcano limited the capability to observe small events.

Table 1. Number of earthquakes at northern California volcanic centers during 24-hour periods following major earthquakes on 25 April (40.37°N, 124.32°W; M 7.0) and 28 June (34.18°N, 116.47°W; M 7.5) 1992. Events with coda durations less than or equal to 10 seconds and greater than 10 seconds are tallied separately. Earthquakes were identified from film records of seismograms from nearby stations. Courtesy of Stephen Walter.

DateLassenShastaMedicine LakeGeysers
Codas (seconds)<= 10> 10<= 10> 10<= 10> 10<= 10> 10
25 Apr 199200010072
28 Jun 199281415120464

Film was also scanned for the 24 hours following the M 7.0 earthquake at 40.37°N, 124.32°W (near Cape Mendocino) on 25 April. Although smaller than the 28 June earthquake, its epicenter was only 20-25% as far from the volcanoes. Furthermore, both the 25 April main shock and a M 6.5 aftershock were felt at the volcanic centers, but no felt reports were received from these areas after the 28 June earthquake. Only the Geysers showed any possible triggered events after the 25 April shock. However, background seismicity at the Geysers is higher than at the other centers, and is influenced by fluid injection and withdrawal associated with intensive geothermal development.

Shasta report. The film record showed no earthquake activity beneath Shasta (~900 km NNW of the epicenter), although telemetry problems limited the ability to detect events below M 2. Of the six earthquakes in the 24 hours following the M 7.5 shock, two were large enough to be recorded by the RTP system. These were centered about 60 km SE of Shasta and about equidistant from Lassen (figure 1). Because the arrival times and S-P sequences of the other four events were similar to those of the two located shocks, it is likely that all had similar epicenters. Occasional M 2 earthquakes have previously occurred in this area, which includes several mapped N-trending normal faults with Quaternary movement. Three days after the M 7.5 earthquake, a M 2.0 shock occurred beneath Shasta's SE flank, followed by a M 2.7 event the next day. Both were centered at about 15 km depth, similar to most earthquakes beneath Shasta in the last decade.

Figure 1. Seismic events in the Shasta/Medicine Lake area that were apparently triggered by the M 7.5 southern California earthquake of 28 June 1992 (circles) compared to 1978-90 seismicity in the region (crosses). Squares mark seismic stations. Courtesy of Stephen Walter.

Information Contacts: Stephen Walter and David Hill, MS 977, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 USA.

Global Volcanism Program | Shasta (2024)

FAQs

What is the purpose of the Global Volcanism Program? ›

The Global Volcanism Program (GVP) is the hub of an international network for monitoring, reporting, and maintaining data related to volcanic activity around the world.

Which volcano is most likely to erupt next? ›

We know that Mount St. Helens is the volcano in the Cascades most likely to erupt again in our lifetimes. It is likely that the types, frequencies, and magnitudes of past activity will be repeated in the future.

What volcano just erupted in 2024? ›

Recent Eruption Information: Kīlauea erupted briefly on June 3, 2024, southwest of the summit region within a closed area of Hawaiʻi Volcanoes National Park. For more information about this eruption, see this webpage: https://www.usgs.gov/volcanoes/kilauea/science/june-2024-kilauea-southwest-rift-zone-eruption.

What is one that is currently erupting or is expected to erupt soon? ›

An active volcano is a volcano that has erupted during the Holocene (the current geologic epoch that began approximately 11,700 years ago), is currently erupting, or has the potential to erupt in the future. A volcano that is not currently erupting but could erupt in the future is known as a dormant volcano.

How many volcanoes are in the United States? ›

The United States has 169 active volcanoes. More than half of them could erupt explosively, sending ash up to 20,000 or 30,000 feet where commercial air traffic flies. USGS scientists are working to improve our understanding of volcano hazards to help protect communities and reduce the risks.

What volcano would destroy the world if it erupted? ›

Some stats on the Yellowstone supervolcano: A super-eruption would equal the force of 1,000 Hiroshima atomic bombs exploding every second. You could fit Tokyo, the world's biggest city, in Yellowstone's super-volcanic crater.

Where are the three super volcanoes in the US? ›

The United States is home to three active supervolcanoes, the USGS has determined: The famous Yellowstone, Long Valley and the Valles Caldera in New Mexico.

What is the most threatening volcano in the US? ›

Lava covered 35.5 square kilometers (13.7 square miles), which included homes, farms, wild spaces, roads, highways and critical infrastructure. Kīlauea is ranked as the U.S. volcano with the highest threat score in the very high threat category. In 1980, a powerful explosion at Mount St.

What volcano is coming to life after 800 years? ›

Volcanic explosions aren't common, and yet a sleeping volcano is coming to life after 800 years. Although rare, even dormant volcanos can show signs of activity. Follow along to learn about Mount Edgecumbe, an inactive volcano showing signs of waking up.

What would happen if Yellowstone erupted? ›

According to the USGS, a “supereruption” at Yellowstone would have regional effects, including falling ash and short-term changes to the global climate that would last years or even decades.

Is Yellowstone volcano going to erupt in 2024? ›

A hazardous hydrothermal explosion occurred in Biscuit Basin on July 23, but it was not associated with any earthquakes and is not an indication of potential future volcanic activity.

What is the most active volcano in the world? ›

Topping the list of most active volcanoes on the planet is Kīlauea on the Hawaiian Islands.

What are 4 signs that a volcano is about to erupt? ›

Notable precursors to an eruption might include:

Noticeable steaming or fumarolic activity and new or enlarged areas of hot ground. Subtle swelling of the ground surface. Small changes in heat flow.

Has Yellowstone ever erupted? ›

Three extremely large explosive eruptions have occurred at Yellowstone in the past 2.1 million years with a recurrence interval of about 600,000 to 800,000 years.

What is the purpose of volcanism? ›

Volcanic materials ultimately break down and weather to form some of the most fertile soils on Earth, cultivation of which has produced abundant food and fostered civilizations. The internal heat associated with young volcanic systems has been harnessed to produce geothermal energy.

What is the purpose of the volcano project? ›

This experiment demonstrates the classic chemical reaction between an acid (namely acetic acid present in the vinegar) and a carbonate (namely sodium hydrogen carbonate present in the baking soda). When exposed to acids, carbonate undergoes a decomposition reaction in which carbon dioxide is released as a gas.

What is the primary goal of the volcano Disaster Assistance Program? ›

At the request of affected governments, VDAP helps fellow scientists monitor volcanic activity, assess hazards, generate eruption forecasts, and develop early warning capabilities to get people out of harm's way.

What is the purpose of volcanology? ›

One of the chief objectives of this research is determining the nature and causes of volcanic eruptions for the purpose of forecasting their occurrence.

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