Newberry Volcano—Central Oregon’s Sleeping Giant

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 2011-3145

2011

the largest volcano in the Cascades 

volcanic arc and covers an area the 

size of Rhode Island. Unlike familiar 

cone-shaped Cascades volcanoes, 

Newberry was built into the shape 

of a broad shield by repeated 

eruptions over 400,000 years. About 

75,000 years ago a major explosion 

and collapse event created a large 

volcanic depression (caldera) at 

its summit. Newberry last erupted 

about 1,300 years ago, and presentday hot springs and geologically 

young lava flows indicate that 

it could reawaken at any time. 

Because of its proximity to nearby 

communities, frequency and size 

of past eruptions, and geologic 

youthfulness, U.S. Geological 

Survey scientists are working to 

better understand volcanic activity 

at Newberry and closely monitor 

the volcano for signs of unrest.

Hidden in plain sight, Oregon’s 

massive Newberry Volcano is 

Rising gradually southward to 4,000 

feet above the City of Bend, Oregon, 

Newberry Volcano appears from Bend as 

a broad ridge on the horizon. Extending 

approximately 75 miles north to south and 

27 miles east to west, the shield-shaped 

volcano and its extensive apron of lava 

flows cover almost 1,200 square miles, an 

area about the size of the State of Rhode 

Island, making it the largest volcano of 

the Cascades volcanic chain. This giant 

volcano is unlike a typical Cascade 

Range cone-shaped volcano (called a 

“stratocone”), such as South Sister to 

the west of Bend or Mount Rainier in 

Washington. Instead, Newberry is a 

“composite volcano” formed by diverse 

styles of eruption and has as many as 

400 volcanic vents scattered across its 

slopes. Numerous lava flows drape its 

flanks, and some that were very fluid when 

erupted—like those typical of Hawaiian 

volcanoes—extend well beyond its base. 

Very explosive eruptions, similar to 

that of Mount St. Helens in 1980, have 

occurred near Newberry’s summit and 

produced high plumes and flows of hot 

volcanic gases and ash (jagged tiny 

particles of rock and volcanic glass). A 

much bigger explosive eruption produced 

the large volcanic depression or “caldera” 

at the summit; its associated volcanic-ash 

deposits can be found as far away as the 

San Francisco Bay Area in California. 

Volcanic activity at Newberry has 

created a unique and spectacular 

landscape, and in 1990 the Newberry 

National Volcanic Monument was 

established within Deschutes National 

Forest. Operated by the U.S. Forest 

Service, the monument encompasses 

all of the Newberry caldera, parts of the 

upper slopes of the volcano, and most 

of the volcano’s “Northwest Rift Zone.” 

Newberry caldera holds two beautiful 

lakes, Paulina Lake and East Lake, 

popular for fishing, boating, swimming, 

and camping.

How Did Newberry Grow to be the 

Largest Volcano in the Cascades? 

Newberry Volcano lies east of the 

Cascades volcanic crest at the west 

margin of a broad volcanic region 

known as the High Lava Plains. The 

high-standing part of Newberry covers 

U.S. GEOLOGICAL SURVEY and the U.S. FOREST SERVICE—OUR VOLCANIC PUBLICLANDS

Newberry Volcano, Oregon, is the largest volcano in the Cascades volcanic arc. This north-facing view taken 

from the volcano’s peak, Paulina Peak (elevation 7,984 feet), encompasses much of the volcano’s 4-by-5-milewide central caldera, a volcanic depression formed in a powerful explosive eruption about 75,000 years ago. 

The caldera’s two lakes, Paulina Lake (left) and the slightly higher East Lake (right), are fed in part by active hot 

springs heated by molten rock (magma) deep beneath the caldera. The Central Pumice Cone sits between the 

lakes. The mostly treeless, 1,300-year-old Big Obsidian Flow, youngest lava flow on the volcano, is surrounded 

by forest south of the lakes. (Photograph by Robert Jensen.)

FOREST SERVICE

DEPARTMENT OF AGRICULTUR

U E

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about 40 miles north-south by 25 miles 

east-west and encompasses nearly 

all of the volcano’s vents. However, 

Newberry’s lava flows extend much 

farther than this high part and to 

the north include the area of what is 

now downtown Bend, as well as the 

Redmond Municipal Airport. About 

350,000 years ago, an early lava flow 

erupted from Newberry and flowed 

north until it reached Smith Rock, 

where it filled and moved down the 

channel of the Crooked River and also 

shifted the channel of the Deschutes 

River. 

Growth of the broad Newberry 

shield began about 400,000 years 

ago. Newberry caldera was created 

about 75,000 years ago by a major 

explosive eruption and collapse event. 

This was the most recent of at least 

three caldera-forming eruptions that 

lofted pumice (frothy volcanic glass) 

high into the air and spread flows of 

extremely hot gases, ash, and pumice, 

called “pyroclastic flows,” across the 

volcano’s surface. Later lava flows 

have partly buried the deposits from 

this eruption, but one exposure can 

be seen at Paulina Creek Falls, where 

a deposit of pyroclastic flow and fall 

material was so hot that ash and pumice 

particles were welded together and then 

cooled into solidified rock. 

flow that underlies downtown Bend 

and the Redmond airport is from that 

same eruption. Once the caldera was 

formed, more eruptions began to fill it 

with lava flows, and lava also erupted 

at numerous sites outside the caldera, 

covering much of the volcano’s north 

and south flanks. Between the end of 

the last Ice Age (about 12,000 years 

ago) and 7,700 years ago, Newberry 

Volcano erupted at least a dozen times. 

Eruption that Formed Crater Lake 

Covers Newberry with Ash

About 7,700 years ago, a massive 

eruption caused the collapse of ancient 

“Mount Mazama,” forming a caldera 

that holds present-day Crater Lake, 

Oregon. Winds blew volcanic ash from 

that eruption northeast over Newberry 

Volcano, which is 75 miles away, 

covering much of it in a blanket of 

dusty ash and pumice as much as 6 

feet thick on the volcano’s south flank. 

In Newberry caldera, the foundation 

of a Native American house was 

discovered underneath this ash layer, 

known as the Mazama ash, suggesting 

that the eruption disrupted an ancient 

human occupation. The ash sharply 

separates lava flows of Newberry’s older 

eruptions from lava flows produced by 

the volcano’s younger eruptions. The 

Newberry Volcano Quick Facts 

Volcano type: shield-shaped composite

Area: 1,200 square miles—about the size of 

Rhode Island

Nearby Towns: Bend, Sunriver, LaPine, and 

Redmond

Population on or near Newberry lavas: about 

200,000

Caldera area: 17 square miles

Elevation: 7,984 feet above sea level—

Paulina Peak summit

Height above Bend: About 4,000 feet

Last eruption: about 1,300 years ago—Big 

Obsidian Flow

Oldest lavas: about 400,000 years

Number of volcanic cones and vents: more 

than 400

Estimated total volume: 120 cubic miles (mi3

) 

(for example, South Sister is 5 mi3

 and Mount 

St. Helens is 6 mi3

)

Volume of Lava Butte cone and flow: Less 

than 1 cubic mile

Before formation of the caldera, 

Newberry’s summit was 500 to 

as much as 1,000 feet higher than 

present-day 7,984-foot Paulina Peak. 

Shortly after the most recent calderaforming eruption, vents on the north 

side of Newberry fed large lava flows 

westward, which created and then 

flowed through Lava River Cave, 

diverting the Deschutes River. The lava 

Looking south from Pilot Butte in Bend, Oregon, the broad shield of Newberry Volcano rises nearly 4,000 feet above the city and the surrounding highdesert terrain. Because this giant volcano does not have the typical cone shape of most Cascades volcanoes and appears to be a small range of low 

mountains, most people do not recognize this sleeping giant as a volcano. The high-standing part of Newberry covers about 40 miles north-south by 

25 miles east-west. Numerous cinder cones (conical hills formed of cooled blobs of frothed lava) are scattered across the flanks of the shield, 

evidence of repeated volcanic activity. (USGS photo by Julie Donnelly-Nolan.)
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Caldera

Rim

This map highlights the Newberry National Volcanic Monument 

and the youngest lava flows on Newberry Volcano which all 

erupted since about 7,700 years ago. Stars show volcanic vents 

that produced these young cones and lava flows. The Northwest 

Rift Zone extends from the caldera to Lava Butte. This fissure 

system erupted about 7,000 years ago and produced many lava 

flows and cones over a distance of about 20 miles. Lava Lands 

Visitor Center is located at the base of Lava Butte; a road leading 

to this cinder cone’s summit is open seasonally. Big Obsidian 

Flow, located within Newberry Caldera, erupted about 1,300 

years ago and is the youngest of all the lavas on Newberry 

Volcano. A trail up onto the obsidian flow is a popular visitor 

destination, as is the trail at Lava Cast Forest, where lava molds 

of trees can be seen. Another popular destination is Lava River 

Cave, an underground lava tube nearly a mile long in an older 

lava flow.

Lavas erupted in the

past 7,700 years

Newberry National 

Volcanic Monument

Lakes and rivers

Volcanic vents

Northwest Rift Zone

EXPLANATION
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This map shows the region surrounding Newberry Volcano, Oregon, which first began to erupt about 400,000 years ago. Extending about 

75 miles north to south and 27 miles east to west, the volcano and its broad apron of lavas (outlined in yellow) cover a total area of almost 

1,200 square miles, making it the largest volcano of the Cascades volcanic chain. Colors show the extent of lavas erupted before the caldera 

formed about 75,000 years ago; after caldera formation; after glaciation but before the catastrophic eruption about 7,700 years ago that 

destroyed ancient “Mount Mazama” and formed Crater Lake, an event that deposited a thick volcanic ash layer over Newberry Volcano; and 

after deposition of Mazama ash. The Deschutes River, which lies on the volcano’s western flank, has at times been shifted to the west by 

Newberry lavas. At other times, eruptions from volcanoes on the Cascades crest to the west have shifted the river channel eastward.

Post-glacial, pre-Mazama 

lavas 12,000 to 7,700 

years old

Post-caldera lavas

75,000 to 12,000 

years old

Pre-caldera lavas

400,000 to 75,000 

years old

Post-Mazama lavas

7,700 years old to 

present

Newberry National 

Volcanic Monument

Lakes and rivers

Volcanic vents 

less than 12,000 

years old

EXPLANATION

Redmond

Airport
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Cinder Cone and Lava Flow

Lava Butte on Newberry Volcano’s northwest flank 

rises about 500 feet above its base. About 7,000 

years ago, explosive activity that produced the 

cinder cone waned and was followed by eruption 

of a rough-surfaced lava flow that reached 

the Deschutes River, temporarily blocking and 

permanently diverting the river. The Lava Lands 

Visitor Center of Newberry National Volcanic 

Monument is located near the cone’s base. (Photo 

by Robert Jensen.)

Ash, Pumice, and Lava Flow

Aerial view south of the youngest and most 

spectacular lava flow at Newberry Volcano, 

1,300-year-old Big Obsidian Flow, a lava flow 

mantled by volcanic glass (obsidian). Its flow 

ridges are highlighted by snow and show the 

pattern of flow away from the main vent near the 

south wall of the caldera. Early in the eruption, very 

explosive activity from this vent produced ash that 

fell as far east as Idaho and pyroclastic flows that 

traveled northward to create deposits that form 

the southeastern margin of Paulina Lake. (Photo 

courtesy of Oregon Department of Transportation)

Pyroclastic Fall and Flow

Paulina Creek Falls are located just west of 

Newberry caldera. Here the water of Paulina 

Creek, the only creek that flows year-round on 

Newberry Volcano, spills over welded pyroclastic 

fall and flow deposits that were emplaced as 

sheets of hot ash and pumice that record pulses 

of activity during the explosive caldera-forming 

eruptions about 75,000 years ago. (Photo by 

Robert Jensen.)

U.S. Geological Survey monitoring of Newberry Volcano will in most instances be able to provide warnings weeks to months before 

most impending hazardous volcanic activity. These warnings along with community emergency-response plans should provide 

sufficient time for orderly evacuations of people and property. Volcano hazards at Newberry include:

Lava flows—Fluid lavas may flow downslope from vents on Newberry’s flanks. The most severe hazards scenario for this type of 

eruption would be for lava to enter populated areas, burning and burying structures, and blocking Highway 97 or other roads. Lava 

flows could also ignite forest fires and temporarily block the Deschutes River, causing flooding upstream from rising waters and 

downstream flooding after the blockages are overtopped or bypassed.

Ash, pumice, and cinders (collectively named tephra)—Consisting of pumice, rock fragments, and small particles of volcanic 

glass, tephra is produced by eruptions such as the one that created the cinder cone of Lava Butte, and the early explosive phase of 

the eruption that generated the Big Obsidian Flow about 1,300 years ago and deposited windblown ash as far away as Idaho. Cinder 

cone eruptions on the volcano’s flank would produce relatively small volumes of tephra that would mostly accumulate close to the 

erupting vent, but pumice and ash eruptions from Newberry caldera could send larger amounts of ash to high altitudes, where it could 

be blown by wind to populated regions and also become a hazard to aviation. Hot cinders and ashfall would likely ignite forest fires, 

and large volumes of gas would be released. Breathing ash particles and volcanic gases can irritate eyes and lungs and cause health 

issues. 

Pyroclastic flows—Eruptions of hot ash, pumice, and gases formed a pyroclastic flow deposit about 75,000 years ago as part of the 

eruption that created Newberry caldera. These infrequent but extraordinarily hot and fast moving flows would move quickly down the 

slopes of Newberry and be very destructive.

Earthquakes and faulting—In the event of an eruption, swarms of small earthquakes will accompany magma (molten rock) 

movement beneath the surface of Newberry Volcano. Although most such volcanic earthquakes are too small to cause damage away 

from the volcano, ground breakage could generate “fault scarps,” which are linear fractures that could cut the surface of Newberry 

Volcano.

Hazards from Newberry Volcano

younger rocks attest to Newberry’s 

many geologically recent eruptions and 

are a warning that this “sleeping giant” 

could awaken again at any time.

The first eruptions after deposition 

of the Mazama ash came from a 

fissure that opened through the middle 

of Newberry caldera. The eruption 

formed a ridge that divides East Lake 

from Paulina Lake. Along the fissure 

are the Interlake Obsidian Flow and 

Central Pumice Cone. The cone rises 

700 feet above East Lake. It was built 

explosively when hot molten rock 

(magma) cooled and shattered after 

entering the lake water. 

Northwest Rift Zone and Caldera 

Eruptions Form Frequently Visited 

Newberry Landmarks

Shortly after the eruptions that 

formed the Interlake Obsidian Flow 

and Central Pumice Cone, less 

explosive, more fluid lavas erupted 
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Julie M. Donnelly-Nolan, Wendy K. Stovall, David W. 

Ramsey, John W. Ewert, and Robert A. Jensen

Edited by James W. Hendley II

Graphic design by Stephen L Scott, Wendy K. Stovall, 

and David W. Ramsey

COOPERATING ORGANIZATION

U.S. Forest Service

For more information contact:

U.S. Geological Survey

David A. Johnston Cascades Volcano Observatory

1300 SE Cardinal Court, Bldg. 10, Suite 100

Vancouver, WA 98683-9589

Tel: (360) 993-8900, FAX: (360) 993-8980

e-mail: cvo@usgs.gov

http://volcanoes.usgs.gov/

This Fact Sheet and any updates to it are available online at 

http://pubs.usgs.gov/fs/2011/3145/

Why Monitor Newberry Volcano? 

The U.S. Geological Survey (USGS) considers Newberry 

Volcano to be a very high threat volcano because of its 

recent volcanic activity (within the past 1,500 years) in an 

area where numerous people live. Monitoring can help 

scientists detect signs that the volcano is reawakening 

so that they can warn nearby communities of impending 

hazardous activity. USGS monitoring stations at 

Newberry, like the one shown here, contain instruments 

to detect the early and subtle signs of a reawakening 

volcano, including both a Global Positioning System (GPS) 

receiver, which measures swelling or deflation of the 

ground, and seismic instruments, which detect distinctive 

volcanic earthquakes caused by molten rock (magma) 

movement beneath a volcano. Data from the USGS 

monitoring network at Newberry Volcano is available at 

http://volcanoes.usgs.gov. (USGS photo by Liz Westby.)

When a volcano is well monitored, we gain the precious 

commodity of time—time to work with and educate those 

at risk, time to develop evacuation plans, and time to 

mitigate hazards to critical infrastructure.

from numerous cinder and spatter 

cones—conical hills formed of cooled 

blobs of ejected frothed lava. About 

7,000 years ago, a 20-mile-long fissure 

system extending northwest from 

the caldera opened up, forming the 

Northwest Rift Zone. Numerous vents 

erupted, including 500-foot-high Lava 

Butte, which spawned a lava flow that 

temporarily dammed the Deschutes 

River. In places, fluid lavas surrounded 

and burned trees, leaving behind 

hollow molds, like those found along 

the trail at Lava Cast Forest. 

The most recent eruption at 

Newberry, about 1,300 years ago, took 

place within the caldera. Explosive 

plumes of volcanic ash and pyroclastic 

flows were followed by slower lava 

flows of volcanic glass (obsidian) that 

created the spectacular Big Obsidian 

Flow. Not only did more than 10 feet of 

ash and fragments of volcanic rock fall 

inside the eastern caldera, but the ash 

can be found as far to the east as Idaho.

Both caldera lakes, Paulina Lake 

and East Lake, have hot springs 

with temperatures as high as 135° 

Fahrenheit. In 1981, temperatures 

higher than 500° Fahrenheit at a depth 

of 3,000 feet were found in a U.S. 

Geological Survey (USGS) drill hole 

sited in the center of the caldera. These 

temperature measurements indicate that 

an active magma system lies beneath 

Newberry Volcano.

Research and Monitoring Reduce 

Risk in Future Eruptions

Because Newberry Volcano has 

erupted relatively recently (within 

the past 1,500 years) and more than 

200,000 people live nearby, the 

USGS considers it a very high threat 

volcano. USGS scientists are studying 

Newberry’s geologic history to further 

understand the volcano’s past behavior 

and to make better assessments of 

future long-term volcanic hazards. 

Geologic research about a volcano’s 

past history allows scientists to make 

assessments of potential future hazards, 

thus enabling communities to make 

wise land-use planning decisions and 

to prepare emergency-response plans. 

Because volcanoes often have long 

periods of quiet that are punctuated 

by eruptive activity, scientists are 

also monitoring Newberry to detect 

any signs that this sleeping giant is 

reawakening. Seismometers that are 

installed on and around the volcano can 

measure earthquakes associated with 

the movement of magma and volcanic 

gas beneath the surface of Newberry, 

and Global Positioning System (GPS) 

instruments can detect and measure 

swelling of the volcano caused by 

magma accumulation underground. 

Newberry Volcano is certain to erupt 

again. If signs of volcanic unrest at 

Newberry are detected, the USGS will 

issue advisories on the likely courses 

of events. The work of USGS scientists 

at Newberry is only part of the USGS 

Volcano Hazards Program’s ongoing 

efforts to protect people’s lives and 

property in all of the volcanic regions 

of the United States.