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Landslide Inventory and Deep-Seated Landslide Susceptibility

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California is host to every type of volcano. The specific hazards to people and property depend on which volcano erupts, the style (effusive or explosive), the volume of lava, the location of the vent, the eruption duration, and local hydrologic (water) conditions. The severity of the hazard generally decreases with distance from the volcano vent.

Threat rankings issued by the U.S. Geological Survey (USGS) for California identify fifteen volcanic centers of Low-, Moderate-, High-, or Very High Threat. The USGS California Volcano Observatory (CalVO) is responsible for assessing the potential hazards associated with these "watch list" volcanoes and providing civil authorities, as well as the public, with timely and accurate information to mitigate, plan, and respond effectively to volcanic activity.

At least seven California volcanoes-Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, and Salton Buttes - have partially molten rock (magma) deep within their roots, and research on past eruptions indicates they will erupt again in the future. The types of volcanic hazards that can unfold depend upon the specific volcano and the type of eruption.
Explosive eruptions are both destructive and life-threatening
Explosive volcanic eruptions blast lava fragments (tephra) and gas into the air with tremendous force from a volcanic vent. The finest particles, called volcanic ash, billow upward, forming an eruption column that can attain stratospheric heights in minutes. Simultaneously, searing volcanic gas laden with ash and chunks of lava may sweep down the flanks of the volcano as a pyroclastic flow, and ballistics (chunks of solid rock or partially molten lava) may come crashing down around the vent. Ash in the eruption cloud, carried by the prevailing winds, may remain suspended for hundreds of miles before settling to the ground as ash fall.
Effusive eruptions can be destructive, but are typically not life-threatening
During less energetic effusive eruptions, hot, fluid lava may issue from the volcano as lava flows that can cover many miles in a single day. Alternatively, a sluggish plug of cooler, partially solidified lava may push up through a crack during an effusive eruption, creating a lava dome. A growing lava dome may become so steep that it collapses, explosively releasing pyroclastic flows which are potentially as hazardous as those produced during explosive eruptions.
Volcanoes can be hazardous even when not erupting
During and after an explosive or effusive eruption, volcanic hazards are still a concern. Unstable ground, noxious gas emissions, and intense heat from fumaroles (steam vents) and hot springs, are dangerous. Loose volcanic debris on the flanks of the volcano can be mobilized by heavy rainfall or melting snow and ice, forming powerful floods of mud and rock (lahars) resembling rivers of wet concrete. These can rush down valleys and stream channels, destroying roads and bridges and carrying away entire buildings.
Volcanic hazard maps inform planning and decision making
Geologists produce volcanic hazard zone maps and assessments to show the types and locations of hazards that may occur during a future eruption. The USGS has published such maps for some, but not all, of California's Moderate to Very High Threat volcanoes. It is important to remember that hazard zone maps are dynamic-as geologic research progresses, existing maps are updated with additional detail, and new maps are created.

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California has active and hazardous volcanoes

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California is host to every type of volcano. The specific hazards to people and property depend on which volcano erupts, the style (effusive or explosive), the volume of lava, the location of the vent, the eruption duration, and local hydrologic (water) conditions. The severity of the hazard generally decreases with distance from the volcano vent.

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"Beaches are perhaps the most iconic feature of California, and the potential for losing this identity is real. The effect of California losing its beaches is not just a matter of affecting the tourism economy. Losing the protecting swath of beach sand between us and the pounding surf exposes critical infrastructure, businesses and homes to damage. Beaches are natural resources, and it is likely that human management efforts must increase in order to preserve them," said lead author of the study, Sean Vitousek, who was a post-doctoral fellow at the U.S. Geological Survey when he conducted this study. Vitousek is now a professor in the Department of Civil & Materials Engineering at the University of Illinois at Chicago.

Although a majority (72 percent) of beaches in Southern California show historical trends of accretion or getting larger (due to large artificial beach nourishments since the 1930s), future predictions indicate that nearly all of the beaches will experience erosion (will get smaller) due to accelerated sea-level rise.

"Beaches in Southern California are a crucial feature of the economy, and the first line of defense against coastal storm impacts for the 18 million residents in the region. This study indicates that we will have to perform massive and costly interventions to preserve these beaches in the future under the erosive pressures of anticipated sea level rise, or risk losing many of the economic and protective benefits beaches provide," said USGS geologist and coauthor, Patrick Barnard.

Important for coastal hazard assessment and management planning, CoSMoS-COAST is a numerical model used to predict shoreline-change due to both sea level rise and changing storm patterns driven by climate change.

The model takes into consideration sand transport both along the beach (due to longshore currents) and across the beach (cross-shore transport) by waves and sea-level rise. Although Southern California beaches are a complex mixture of dunes, bluffs, cliffs, estuaries, river mouths, and urban infrastructure, the model is applicable to virtually any coastal setting. Additionally, the CoSMoS model uses information about historical shoreline positions and how beaches change in response to waves and climate cycles such as El Niño, to improve estimates and improve confidence in long-term prediction of coastline changes in Southern California.

Although shoreline change is very hard to predict, scientists are confident in the accuracy and reliability of the model's predictive capability applied to the forecast period (2010-2100), because of how accurately the model is able to reproduce the historical shoreline change between 1995 and 2010.

"The public already has to overcome obstacles in getting to the beach, from limited public transportation to illegally blocked pathways," said California Coastal Commission Executive Director John Ainsworth. "The prospect of losing so many our beaches in Southern California to sea level rise is frankly unacceptable. The beaches are our public parks and economic heart and soul of our coastal communities. We must do everything we can to ensure that as much of the iconic California coast is preserved for future generations."

The full report, " A model integrating longshore and cross-shore processes for predicting long-term shoreline response to climate change," is published online by the American Geophysical Union in their "Journal of Geophysical Research."

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Disappearing Beaches: Modeling Shoreline Change in Southern California

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"Beaches are perhaps the most iconic feature of California, and the potential for losing this identity is real. The effect of California losing its beaches is not just a matter of affecting the tourism economy. Losing the protecting swath of beach sand between us and the pounding surf exposes critical infrastructure, businesses and homes to damage.

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This is a map showing where the San Andreas Fault runs through California.

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Shows coastal Erosion

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WATCH: Pacifica Coastal Erosion Caught on Drone Video

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Scenic hill slopes can be inspiring - or deadly, as we are seeing after the disastrous debris flows that have ravaged the community of Montecito, California in the wake of heavy rains on Tuesday, Jan. 9, 2018. At least 20 people are dead, and four remain missing. More than a hundred buildings have been destroyed or damaged by moving walls of mud and boulders that rumbled down creeks and canyons into houses and roads.

As mountains rise, erosion tears them down. And Southern California's mountains are rising fast, squeezed up by the action of the region's active faults. This produces steep slopes that erode quickly, though much of that erosion happens in infrequent events, such as big rainstorms right after big wildfires.

We know that risks vary across the terrain and that some places in landslide-prone zones are more dangerous than others. In some regions the riskiest areas are well downslope or downstream of slide-prone slopes, in the places where debris runs out and comes to rest. Unfortunately, few people are aware of these risks when developers build in and around landslide-prone mountains.

A predictable disaster

The U.S. Geological Survey estimates that landslides kill 25 to 50 people a year in the United States - more than earthquakes or volcanoes. Yet landslides receive far less attention and research funding than other natural hazards.

Part of the problem is that when a large earthquake strikes, the whole region feels it. But landslides tend to impact localized areas, so they rarely attract widespread attention, except in devastating cases like Montecito. Furthermore, different kinds of landslides present very different hazards. Assessing landslide risks requires an understanding of how erosional processes shape Earth's surface in different regions.

In a general sense, the threat to Montecito was clear. Scientists and planners have known for decades that the mountains of Southern California are shaped by a cycle of fire, rain and debris flows. Back in 1989, when I was a graduate student studying landslides, journalist John McPhee published his acclaimed book "The Control of Nature." In it, McPhee described scenes of devastation resulting from intense rainfall running off of wildfire-charred slopes to roar down canyons around Los Angeles.

The Montecito disaster did not come as a complete surprise. Indeed, the U.S. Geological Survey warned of high potential for disastrous landslides if intense rain fell on mountainsides around Santa Barbara that had been scorched by the Thomas wildfire in December. When that perfect storm landed, it hit bare, baked soil that could not readily absorb water. So the rain ran off, picking up soil, boulders and debris as it surged down canyons and streams. These debris-charged torrents slowed only where steep channels gave way to gentler slopes.

Most of the damage occurred along the run-out pathways of the debris flows - areas where material can flow after it starts sliding downhill. Yet landslide hazard maps generally don't show predicted run-out zones. Instead, they typically show only the locations of the source areas where landslides are likely to start.

Better information for residents

There are reasons why people keep building homes in landslide-prone areas. Some decide it's worth the risk. In Seattle, where I live, steep slide-prone slopes tend to offer the best, and most expensive, views. Conversely, in low-income regions such as Appalachia and many developing countries, the poor often are pushed up onto potentially unstable hillsides. Generally, however, I suspect that many Americans living in landslide country are simply unaware of potential hazards that the lay of the land presents to their homes, neighborhoods and businesses.

Sometimes politics or greed plays a role. After Hurricane Frances hammered North Carolina in 2004, the state legislature approved a program to map landslide hazards. But once the first maps were produced, the program was canceled over concerns that the maps would affect land values and be used to regulate development.

Without this kind of information, residents are physically and financially exposed. "Earth movement," such as landslides, generally is not covered by homeowner's insurance policies. And by the time a landslide comes, developers are long gone, leaving homeowners holding the bag.

And, of course, different types of landslides pose different risks. In the slow-moving Rattlesnake Ridge landslide in central Washington state, a 20-acre parcel of land is sliding downhill about a foot and half per week. Residents have been moved out of the at-risk zone, and engineers and geologists are monitoring the site in real time to evaluate and update hazard assessments.

In contrast, the Oso landslide north of Seattle on March 22, 2014 was so large and fast-moving that even a real-time warning would not have prevented tragedy. This disaster killed 43 people in a couple of minutes when an entire hillside collapsed. In response, Washington state has started posting detailed topographical maps online for use in identifying areas at risk for generating landslides. But hazard maps still don't identify potential downhill run-out zones.

It's time to get serious about landslide zoning, in the way that the federal government maps areas at serious risk of flooding. Landslide hazard maps delineating potential run-out zones should be part of local land use planning. These maps could help guide zoning decisions and better inform homeowners, banks and insurance companies of potential risks. Ultimately, the best way to reduce landslide risk is to avoid building things we value in places where run-out is likely. For when there's no controlling nature, there's only living with her.

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Deadly California mudslides show the need for maps and zoning that better reflect landslide risk

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Scenic hill slopes can be inspiring - or deadly, as we are seeing after the disastrous debris flows that have ravaged the community of Montecito, California in the wake of heavy rains on Tuesday, Jan. 9, 2018. At least 20 people are dead, and four remain missing.

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Shows areas of past volcanic activity in California

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Eruption in 1915

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This 20-minute film provides a brief introduction to Lassen Volcanic National Park. It is normally only shown in park visitor centers and is being provided online for a limited time during COVID-19 response. The film was funded by Lassen Park Foundation (lassenparkfoundation.org) through donations from visitors like you.

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Summary

Mount Shasta began forming on the remnants of an older, similar volcano that collapsed 300,000 to 500,000 years ago. The collapse spawned one of the largest landslides known on Earth, covering more than 440 km ² (170 mi ²) of Shasta Valley to the northeast. Activity over the last 300,000 years includes long intervals of quiet interrupted by shorter spans of frequent eruptions. Eruptions at about 11,000 years ago built Black Butte and Shastina on the western flanks of Mount Shasta. In the last few millennia, smaller eruptions have broken out at the volcano's summit and from vents on its upper east flank. USGS scientists are working on constraining the age of the most recent eruption. Preliminary work indicates the volcano erupted in the past 200-300 years. Hot springs and volcanic gases seep from the summit indicating a relatively young and still-hot system. Non-volcanic shedding of young volcanic rock and ash from Mount Shasta's steep slopes occurs during heavy rainfall or glacial floods. In the last 1,000 years, more than 70 mudflows have inundated stream channels. The record of eruptions over the last 10,000 years suggests that, on average, at least one eruption occurs every 800 to 600 years at Mt Shasta. USGS and UNAVCO seismic and geodetic networks provide real-time volcano monitoring data. Earthquake activity has been low for the last few decades and ground deformation is negligible.

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Mount Shasta began forming on the remnants of an older, similar volcano that collapsed 300,000 to 500,000 years ago. The collapse spawned one of the largest landslides known on Earth, covering more than 440 km 2 (170 mi 2) of Shasta Valley to the northeast.

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Tom Bean/Corbis

Amos and colleagues' study suggests that seasonal and decadal water extraction in the nearby southern Central Valley stresses the San Andreas Fault system, causing variations in seismicity and promoting future earthquakes.

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Figure 1: Aerial view of the San Andreas Fault along the Carrizo Plain, central California.

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Tom Bean/Corbis Amos and colleagues' study suggests that seasonal and decadal water extraction in the nearby southern Central Valley stresses the San Andreas Fault system, causing variations in seismicity and promoting future earthquakes.

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Damage done by Mount Saint Helens Volcanic Eruption

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Damage done by Mount Saint Helens Volcanic Eruption

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The California Geological Survey studies earthquakes to help Californians plan and build earthquake resistant communities. We record the strong ground motion from earthquakes, study the distribution of historic earthquakes and evaluate faults that are the source of earthquakes. We combine that information to prepare maps showing the potential for ground shaking, fault rupture, liquefaction and seismically induced landsliding.

Earthquake Probabilities

Earthquake probabilities are calculated by projecting earthquake rates based on earthquake history and fault slip rates. The result is expressed as the probability that an earthquake of a specified magnitude will occur on a fault or within an area. The Uniform California Earthquake Rupture Forecast represents the best available science for authoritative estimates of the magnitude, location, and likelihood of potentially damaging earthquakes in California.

Earthquake Shaking Hazards

Earthquake shaking hazards are calculated considering earthquake magnitudes and rates, the decrease in earthquake shaking with distance, and amplification of shaking by soils. The result is expressed as the level of ground shaking (as a percentage of gravity) that on average occurs every 2,500 years. These calculations for California are part of a cooperative project between USGS and CGS, and are part of National Seismic Hazard Maps.

Earthquake Loss Estimation

The effects of potential earthquakes are described by statewide earthquake loss estimation and planning scenarios. An earthquake planning scenario is a description of a hypothetical earthquake, including projected ground shaking, damage, social disruption and economic losses. The long term effects of possible earthquakes also can be estimated and described as annualized losses: the average loss or casualties per year. Earthquake loss estimation and planning scenarios provide useful information in preparing emergency response plans, developing earthquake hazard mitigation strategies, and evaluating the nature and scope of response and recovery efforts prior to the earthquakes.

What to do Before, During, and After an Earthquake

Knowing how to prepare for and survive a major earthquake will be critical in California sometime in the coming years.

How to Prepare

Plan on fending for yourself for at least three days, preferably for a week. Electricity, water, gas and telephones may not be working after an earthquake. The police and fire departments are likely to be tied up.

Decide in advance how and where your family will reunite if separated during a quake.Do in-home practice drills. You might choose an out-of-the-area friend or relative that family members can call to check on you.

What to do During an Earthquake

If you're indoors, stay there.Get under -- and hold onto --a desk or table, or stand against an interior wall. Stay clear of exterior walls, glass, heavy furniture, fireplaces and appliances. The kitchen is a particularly dangerous spot. If you're in an office building, stay away from windows and outside walls and do not use the elevator. Many are certain that standing in a doorway during the shaking is a good idea.That's false, unless you live in an unreinforced adobe structure; otherwise, you're more likely to be hurt by the door swinging wildly in a doorway or trampled by people trying to hurry outside if you're in a public place.

If you're driving, move the car out of traffic and stop. Avoid parking under or on bridges or overpasses. Try to get clear of trees, light posts, signs and power lines. When you resume driving, watch out for road hazards.

If you're in a mountainous area, beware of the potential for landslides. Likewise, if you're near the ocean, be aware that tsunamis are associated with large earthquakes. Get to high ground.

If you're in a crowded public place, avoid panicking and do not rush for the exit. Stay low and cover your head and neck with your hands and arms.

What to Do After an Earthquake

Check for fire or fire hazards. If you smell gas, shut off the main gas valve. If there's evidence of damage to electrical wiring, shut off the power at the control box.

Listen to the radio for important information and instructions. Remember that aftershocks, sometimes large enough to cause damage in their own right, generally follow large quakes.

If you leave home, leave a message telling friends and family your location.

Earthquake Frequently Asked Questions

What is an earthquake and what causes earthquakes?

An earthquake is a shaking of the ground caused by the sudden breaking and shifting of rock beneath the Earth's surface. Earthquakes occur when the two sides of a fault slip suddenly against each other. In California, the Pacific and North American plates creep past each other in opposite directions, about 1.5 inches per year. Friction between the plates causes some parts to snag, then break free in sudden, jerking movements. Those movements emit waves of energy that travel through the ground, causing the shaking you feel.

What is a fault?

A fault is a fracture in the crust along which one side has moved relative to the other side. Faults can be very small or hundreds of miles long. The earth's crust is composed of huge plates that are in slow but nearly constant motion. Part of California is on the Pacific Plate, and part is on the North American Plate. The San Andreas Fault, which runs from the Salton Sea in Imperial County to Cape Mendocino in Humboldt County, is the boundary between these plates. Sometimes one block of the crust moves up while the other moves down, sometimes they move horizontally in opposite directions (that's what's happening with the San Andreas Fault; Los Angeles is creeping closer to San Francisco). Some faults are well known and easy to spot, such as the San Andreas. Others are underground, with nothing on the surface revealing their presence (a blind thrust fault). The 1994 Northridge earthquake was caused by a blind thrust fault.

How common are faults in California?

There are hundreds of identified faults in California; about 200 are considered potentially hazardous based on their slip rates in recent geological time (the last 10,000 years). More than 70 percent of the state's population resides within 30 miles of a fault where high ground shaking could occur in the next 50 years.

Does California have more and bigger earthquakes than anyplace else?

Actually, Alaska has more earthquakes and the biggest ones in the U.S. The largest earthquake in history occurred in Chile (a magnitude 9.5 on May 22, 1960). The biggest earthquake in the contiguous 48 states was the magnitude 7.9 Fort Tejon quake on Jan. 9, 1857.

How often do earthquakes happen?

The National Earthquake Information Center (U.S.) reports 12,000-14,000 earthquakes a year around the world, or 35 a day. Throughout the world, there are one "great" (magnitude 8.0 or more), 18 "major" (7.0-7.9), 120 "large" (6.0-6.9) and 1,000 "moderate" (5.0-5.9) earthquakes in an average year. Each year, California generally gets two or three earthquakes large enough to cause moderate damage to structures (magnitude 5.5 and higher). Earthquakes can occur at any time of the year.

What is an earthquake's hypocenter? What is the epicenter?

Earthquake ruptures usually begin far under the surface of the Earth. The point on a fault where rupture initiates is referred to as the focus or hypocenter of an earthquake. The hypocenter is described by its depth in kilometers, its map location in latitude and longitude, its date and time of occurrence, and its magnitude (a measure of the amount of energy radiated as seismic waves). The term epicenter, which is more commonly used to refer to an earthquake location, is the point on the earth's surface directly above the hypocenter. The description of an epicenter is the same as for a hypocenter except the depth is omitted.

How are earthquakes recorded and measured?

There is a network of seismic monitoring stations throughout California and in other parts of the country and world. Sensors and recorders in each station measure and record ground vibrations produced by earthquakes. They measure acceleration, velocity, and displacement on three axes of motion--horizontal (x, y), and vertical (z). They transmit the information to computers which further process the data. The data from multiple stations enable us to determine the time, epicenter, and focal depth of an earthquake. Also, estimates can be made of an earthquake's relative intensity and amount of energy it released.

How much power does an earthquake release?

The strength of an earthquake is generally expressed in two ways: magnitude and intensity. The magnitude is a measure that depends on the seismic energy radiated by the earthquake as recorded on seismographs. An earthquake's magnitude is expressed in whole numbers and decimals (e.g., 6.8). The intensity at a specific location is a measure that depends on the effects of the earthquake on people or buildings. Intensity is expressed in Roman numerals or whole numbers (e.g., VI or 6). Although there is only one magnitude for a specific earthquake, there may be many values of intensity (damage) for that earthquake at different sites.

A magnitude 6.0 quake releases approximately as much energy as 6,270 tons of TNT, a magnitude 7.0 199,000 tons, a magnitude 8.0 6.27 million tons and a magnitude 9.0 99 million tons. Of course, all that energy is not focused in one particular spot, but spreads out in waves.

What factors influence what you feel in an earthquake?

There are three major factors: magnitude, your distance from the fault, and local soil conditions. Magnitude is discussed above. As for distance, the seismic waves that cause the shaking become less intense farther from the fault. Certain soil conditions amplify the shaking; generally, the looser the soil, the greater the amplification. Although most of San Francisco escaped serious damage in Loma Prieta, those with unconsolidated landfill or soft soils (such as the Marina District) suffered serious damage. The ground motion in such areas was 10 times stronger than at neighboring sites on rock.

What is a tsunami?

Sometimes called seismic sea waves (or, incorrectly, tidal waves), a tsunami is a series of waves generated by large earthquakes that create vertical movement on the ocean floor. Tsunamis can reach more than 50 feet in height, move inland several hundred feet and threaten life and property. Often, the first wave of a tsunami is not the largest. Tsunamis can occur on all coastal regions of the world, but are most common along margins of the Pacific Ocean. Tsunamis can travel from one side of the Pacific to the other in a day, at a velocity of 600 miles an hour in deep water. A locally generated tsunami may reach the shore within minutes.

Can earthquakes be prevented?

There's no way to stop an earthquake, but there are ways to build safer buildings and structures and otherwise be prepared for them. Building codes in California are updated often as new information comes in. While earthquakes are a deadly threat, there have been few earthquake-related deaths in California relative to places with less stringent codes or enforcement, such as Turkey and China.

Sources: California Geological Survey/California Geology, USGS, Arkansas Center for Earthquake Education and Technology Transfer, Governor's Office of Emergency Services, Federal Emergency Management Agency, National Science Foundation, Southern California Earthquake Center, American Red Cross, Center for Earthquake Research and Information/University of Memphis.

Earthquake Myths

If the Earth moves beneath our feet, is it because Atlas shrugged? In a bygone era, some folks may have believed that theory, but even today there are earthquake anecdotes that aren't exactly the stuff of modern science. Let's take a look at them:

MYTH: Dogs and other animals can "sense" when an earthquake is going to strike

It's impossible to determine whether a dog is behaving in an unusual manner because it smells an earthquake coming or a cat across the street. Changes in animal behavior sometimes have been observed prior to earthquakes, but that behavior is not consistent, and sometimes there's no perceptible behavior change prior to an earthquake.

MYTH: Earthquakes occur during "earthquake weather"

The common misconception that earthquakes occur during hot and dry weather dates to the ancient Greeks. Earthquakes take place miles underground, and can happen at any time in any weather.

MYTH: Big earthquakes always occur early in the morning

Just as earthquakes don't care about the weather, they can't tell time. The 1940 Imperial Valley quake was at 9:36 p.m., the 1989 Loma Prieta quake at 5:02 p.m. People who perpetuate the time and weather myths tend to remember the earthquakes that fit the pattern and forget about the ones that don't.

MYTH: California could fall into the sea because of an earthquake

The San Andreas Fault System is the dividing line between two tectonic plates. The Pacific Plate is moving in a northwesterly direction relative to the North American plate. The movement is horizontal, so while Los Angeles is moving toward San Francisco, California won't sink. However, earthquakes can cause landslides, slightly changing the shape of the coastline.

MYTH: The ground can open up and swallow people

You've seen the image in books, movies and TV shows. That's not how it works. If a fault could open up, there wouldn't be any friction. Without friction, there's no earthquake. But earthquakes cause settling and other ground deformation that can include open fissures into which people, cars, etc., can fall.

MYTH: The safest place to be in an earthquake is under a doorway

That's true only if you live in an unreinforced adobe home. In a modern structure the doorway is no stronger than the rest of the building. Actually, you're more likely to be hurt (by the door swinging wildly) in a doorway. And in a public building, you could be in danger from people trying to hurry outside. If you're inside, get under a table or desk and hang on to it.

MYTH: Small earthquakes keep big ones from happening

Each magnitude level represents about 31.6 times more energy released. It takes 32 magnitude 3s to equal the energy released in a magnitude 4, 1,000 magnitude 3s to equal a magnitude 5 ... and a billion magnitude 3s to equal a single magnitude 9. So while a small quake may temporarily ease stress on a fault line, it does not prevent a large temblor.

MYTH: The magnitude of an earthquake determines whether disaster assistance is forthcoming

A magnitude 7 quake in the middle of the desert is likely to do less damage than a magnitude 6 in downtown Los Angeles or San Francisco. It is the magnitude of the damage, not the earthquake, which determines the level of response.

MYTH: We have good building codes, so we must have good buildings

That's true -- provided you're talking about buildings constructed under current building codes. In the case of older buildings, retrofitting -- bringing the building up to modern standards -- is up to the building's owners. There are plenty of buildings in areas of California prone to seismic activity which were built under older codes.

MYTH: Earthquakes are becoming more frequent

Research shows that earthquakes of magnitude 7.0 or greater have remained fairly constant throughout recorded history and have actually decreased in recent years. However, since there are a greater number of seismological centers and instruments capable of locating many small earthquakes that went undetected in earlier years, it may seem as if there are more.

MYTH: There's nothing we can do to protect ourselves from earthquakes

It's true that earthquakes can't be stopped, but you can be prepared. You can put together an earthquake kit (food, water, flashlight, etc.), practice "drop, cover and hold on" drills at home with your family and at work, and develop an earthquake plan (where would you meet family members if you weren't together when an earthquake hit?). Also, remember that standard homeowners insurance doesn't cover damage from earthquakes. For information about earthquake insurance, visit the California Earthquake Authority.

Sources: California Geological Survey/California Geology, USGS, Arkansas Center for Earthquake Education and Technology Transfer, Governor's Office of Emergency Services, Federal Emergency Management Agency, National Science Foundation, Southern California Earthquake Center, American Red Cross, Center for Earthquake Research and Information/University of Memphis.

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California Department of Conservation administers a variety of programs vital to California's public safety, environment and economy. The services DOC provides are designed to balance today's needs with tomorrow's obligations by fostering the wise use and conservation of energy, land and mineral resources.

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San Francisco Earthquake 1989

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Volcano observatories reduce risk around the globe. Here's how we can support them.

When a volcano erupts, there can be global ripples caused by interruptions of air travel, agriculture, and tourism. One way to keep everyone secure is to ensure that volcano observatories around the world have the expertise and resources to detect and forecast volcanic activity, and can provide useful warnings and messages used by both local and global populations.

Two scientists from the USGS Volcano Disaster Assistance Program (VDAP is funded largely by USAID) penned a short overview of ways that different entities such as academia, governments, NGOs, and the global insurance industry can work together to bolster global resilience to volcanic disasters through support of front-line science institutions, like volcano observatories.

The article, Volcano observatories reduce risk around the globe. Here's how we can support them, delves into topics such as infrastructure donation, research and operational motives, and training of observatory staff, while maintaining the key goal of supporting the autonomy and authoritative role of the local observatory.

Volcano Observatories Continue Operations Amid COVID-19

The five volcano observatories of the USGS Volcano Hazards Program continue to monitor the volcanoes of the United States and issue forecasts and regular updates of volcanic activity. Through telework and other adaptations we continue to maintain our monitoring networks and analysis of the incoming data. Our field crews visit field stations as needed to maintain the quality and functionality of the network. All work will follow federal government guidelines to ensure public safety and the safety of our staff. The health and safety of the public and our employees are our highest priorities, and we continue to follow guidance from the White House, the CDC, and state and local authorities, as we implement teleworking, social distancing and virtual meeting tools.

Our priority is to continue the important work of the Department of the Interior and the USGS, while also maintaining the health and safety of our employees and community. Based on guidance from the White House, the CDC, and state and local authorities, we are shifting our operations to a virtual mode and have minimal staffing within our offices. If you need additional assistance, please contact vhpweb@usgs.gov.

Read Our Two Weekly Volcano Observatory Science Articles

Scientists within the USGS Volcano Hazards Program operate from within five U.S. volcano observatories. One of the primary goals of the observatories is to be an authoritative source for enlightening information about our Nation's volcanoes.

The Hawaiian Volcano Observatory (HVO), the oldest of the five, has a long history of writing regular articles about volcanic activity and scientific research on the Hawaiian volcanoes. HVO's weekly article, "Volcano Watch," entered its 27th year of publication in November 2017. The entire catalog of articles can be accessed and searched on their website. New articles are published every Thursday afternoon.

Taking lead from HVO, the Yellowstone Volcano Observatory (YVO), the newest of the five observatories, began a weekly article on the first day of 2018. This new column- the "Yellowstone Caldera Chronicles"-is posted each Monday on the homepage of YVO's website . Like HVO's Volcano Watch series, the YVO Chronicles are peer-reviewed and edited before publication.

If you are interested in learning more about a specific topic related to Yellowstone or Hawaiian volcanism, please contact us. We will certainly answer, and you may see a longer-winded answer in a future Volcano Watch or Yellowstone Caldera Chronicle article.

Volcanic Unrest is Persistent in Alaska. No Current Eruption in Hawaii.

The Alaska Volcano Observatory website (AVO) includes complete information about volcanoes in Alaska.

Great Sitkin, located in the central Aleutian Islands, has been in a state of volcanic unrest since February 26, 2020. Seismicity is above background levels.

Mount Cleveland, located in the central Aleutian Islands, has been in a state of volcanic unrest since June 17, 2015. Explosive eruptions can send ash to altitudes hazardous to aviation.

Semisopochnoi, located in the western Aleutian Islands, has been in a state of volcanic unrest since July 5, 2019. Seismicity is above background levels. No explosive activity has been detected on the Adak infrasound array.

Shishaldin, located in the eastern Aleutian Islands, has been in a state of volcanic unrest since July 12, 2019. Seismicity is above background levels and elevated surface temperatures have been observed at the summit.

The Hawaiian Volcano Observatory website offers information about volcanoes in Hawaii.

Kīlauea Volcano on the Island of Hawai'i is not erupting. Eruptive activity ceased in mid-August, 2018.

Mauna Loa Volcano on the Island of Hawai'i is not erupting. Earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. An eruption is not imminent and current rates are not cause for alarm. However, scientists have detected changes in the shallow magma storage system at Mauna Loa.

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Attribution: Natural Hazards, Volcano Hazards Program Office, Region 9: Columbia-Pacific Northwest, Region 10: California-Great Basin, Region 11: Alaska, Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands), Volcano Science Center, California Volcano Observatory, Cascades Volcano Observatory, Hawaiian Volcano Observatory, Yellowstone Volcano Observatory

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Interactive Map Earthquakes where you live

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Interactive Map Earthquakes where you live

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Possible lands slides near coast California

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This map service is unavailable

Description:

This dataset includes: The locations of EPA listed sites that are vulnerable to a 100-year coastal flood with a 1.4 meter sea-level rise. Extents of dune and bluff erosion given a 1.4 meter (approx. 55") sea-level rise for the entire California coast. Extent of a 100-year coastal flood, based on FEMA 100-year flood elevations, with a sea-level rise of 1.4 meters (55 inches) (year 2100). Extent of inundation due to Mean Higher High Water (MHHW), after a 1.4 meter sea-level rise (scenario for year 2100), for the California coast (excluding the San Francisco Bay). The current inundation due to MHHW was based on NOAA tide stations elevation data (mhhw_2000 raster), to which 140 centimeters were added to the Z-value to generate this data. For details concerning methods, see the OPC SEA LEVEL RISE COASTAL EROSION MAPPING document from Philip Williams and Associates, LTD, from December 18th, 2008.

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California Sea Level Rise Coastal Erosion Mapping

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This dataset includes: The locations of EPA listed sites that are vulnerable to a 100-year coastal flood with a 1.4 meter sea-level rise. Extents of dune...