This photograph shows the historic Kalahikiola Congregational Church, Kapa`au, North Kohala District, 

Island of Hawaiÿi. The church, originally built in 1855, and its unreinforced mortared-stone facade were 

heavily damaged by two magnitude 6+ earthquakes that struck the northwest coast of the Island of 

Hawaiÿi on October 15, 2006. Unreinforced masonry structures are particularly vulnerable to quake damage. (Copyrighted photo by Michael Darden/West Hawaii Today, used with permission.)

Each year, thousands of earthquakes occur in the State of Hawaii. 

As in other seismically active regions 

around the world, the vast majority 

of these are microearthquakes. Earthquakes in the State are detected by 

sensitive seismometers operated by 

the Hawaiÿi Integrated Seismic Network. Sometimes the earthquakes are 

large enough to be felt by people. Less 

frequently, strong quakes occur like 

those that struck the northwest coast 

of the Island of Hawaiÿi on the morning of October 15, 2006—a magnitude 

6.7 quake at 7:07 a.m. and a magnitude 6.0 quake at 7:14 a.m. These earthquakes damaged roads and structures on 

Hawaiÿi and Maui, the islands nearest 

the quakes’ epicenters. 

Earthquakes and Volcanoes

Earthquakes in the Hawaiian Islands 

chain are closely linked to active volcanism. Most quakes occur closest to Kïlauea 

and Mauna Loa Volcanoes, along the southeastern coastline of the Island of Hawaiÿi, 

extending inland beneath the flanks of 

these volcanoes. Earthquake activity is 

also evident at Löÿihi seamount, the State’s 

youngest volcano, about 22 miles (~35 

km) southeast of the Island of Hawaiÿi and 

still some 3,000 feet (1,000 m) beneath the 

surface of the Pacific Ocean. Rates of earthquake activity decrease progressively to the 

northwest, toward the older islands in the 

Hawaiian Islands chain.

Where an earthquake is located typically offers a basic understanding of its 

underlying cause. Earthquake patterns 

showing events closely spaced in time 

with points of origin, or “hypocenters,” 

clustered within the summit caldera 

and rift zone regions of Hawaiÿi’s active volcanoes indicate magma (molten 

1 U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2011-3013 

September 2011

U.S. GEOLOGICAL SURVEY—REDUCING THE RISK FROM VOLCANO HAZARDS

Earthquakes in Hawaiÿi—An Underappreciated but 

Serious Hazard

he State of Hawaii has 

a history of damaging 

earthquakes. Earthquakes in 

the State are primarily the 

result of active volcanism and 

related geologic processes. 

It is not a question of “if” a 

devastating quake will strike 

Hawaiÿi but rather “when.” 

Tsunamis generated by both 

distant and local quakes are 

also an associated threat and 

have caused many deaths in 

the State. The U.S. Geological 

Survey (USGS) and its 

cooperators monitor seismic 

activity in the State and are 

providing crucial information 

needed to help better prepare 

emergency managers and 

residents of Hawaiÿi for the 

quakes that are certain to 

strike in the future.

T
rock) movement within the volcanoes. 

Away from active volcanic centers, 

on faults buried within and beneath 

the flanks of the volcanoes, quakes 

occur in response to stress changes 

resulting from magma movement and 

adjustments to the geologic structure 

of an island. In these regions, quakes 

occur on, and help delineate, active 

fault structures and geometries within 

volcanic edifices. On the Island of 

Hawaiÿi, one such prominent fault 

structure lies at a depth of roughly 6 

miles (~9 km). This is thought to represent the interface between ancient 

oceanic crust and the overlying, much 

younger volcanic edifice. Most of the 

State’s large and damaging historically recorded quakes are thought to 

have occurred along this interface.

Another type of earthquake reflects the flexing or bending of the 

Earth’s crust and upper mantle, or 

“lithosphere,” beneath the weight of 

the Hawaiian Islands. Lithospheric 

earthquakes occur deep beneath the 

Islands and are more common beneath 

Hawaiÿi and Maui, the geologically 

youngest islands. Some of these earthquakes, like the October 15, 2006, 

quakes, can be large and damaging. 

Such quakes are caused by the weight 

of the islands rather than by active 

volcanism. Similar powerful quakes 

could occur beneath older Hawaiian 

Islands and closer to the State’s larger 

and more densely concentrated populations like those on Oÿahu. 

Measuring Earthquake Intensity

Most effects of earthquakes felt 

or observed by people are the result of 

shaking produced by seismic waves. In 

the United States, these effects or the 

“intensity” of a quake are compared 

using the Modified Mercalli Intensity 

(MMI) scale. The effects of a 

quake on the Earth’s surface, 

humans, objects of nature, and 

manmade structures are ranked 

on a scale of I through XII; for 

example, I means not felt and 

XII means total destruction. 

Generally the values are higher 

closest to the quake’s epicenter 

but will vary depending on local 

geology. Historically, the most 

extreme earthquake effects in Hawaiÿi 

were recorded from the April 1868 Great 

Kaÿu earthquake, but this quake predated 

instrumental seismic monitoring in the 

State. Using historical accounts of this 

earthquake, intensities of VII to XII were 

inferred to have occurred on the Island of 

Hawaiÿi, leading the USGS scientists to 

estimate the quake’s magnitude at about 

7.9. The earthquake produced tsunamis 

and landslides and caused stone buildings 

to collapse, killing a total of 77 people.

Earthquakes and Tsunamis

 Hawaiians know that their islands 

have been struck by tsunamis produced 

by distant earthquakes, such as the 1960 

magnitude 9.5 Chilean quake that generated a tsunami, which killed 61 people in 

Hilo, and the March 2011 magnitude 9.0 

quake in Japan. However, many people 

are possibly unaware that large earthquakes in Hawai‘i, like the 1868 Great 

Ka‘u quake, have also produced tsunamis 

with devastating local impacts. The maximum height of the tsunami produced by 

the 1868 earthquake was approximately 

45 feet (14 m) on the southeast coast 

of the Island of Hawai‘i, and 46 people 

were killed by the waves. More recently, 

the 1975 magnitude 7.2 Kalapana earthquake, also along the southeast coast of 

the Island of Hawai‘i, produced a tsunami with maximum height of roughly 

45 feet (14 m), killing two people.

Because of the proximity of source 

zones for earthquakes to low-lying 

2

Kaua‘i

Ni‘ihau

O‘ahu Moloka‘i

Lana‘i

Kaho‘olawe

Maui

Hawai‘i

Pacific Ocean

0 50 100 KILOMETERS

0 50 100 MILES

Magnitude 6

Earthquakes before 1925 are shown in blue

Magnitude 7

N

Large Earthquakes in Hawai‘i, 1823–2010

The largest locally generated tsunami 

in Hawai‘i in the past century was triggered by a magnitude 7.2 earthquake 

that struck the Island of Hawai‘i in November 1975. Waves reached as high 

as 45 feet (14 m) above sea level near 

the quake’s epicenter on the southeast 

coast of the island. The tsunami killed 

two people and caused property damage of about $1.4 million (1975 dollars), 

including damage to this house in 

Punalu‘u (top) and boat in Hilo (bottom). (House photo by David Shapiro 

and boat photo by Hugh Clark, courtesy 

Honolulu Star-Advertiser; used with 

permission.)

The State of 

Hawaii has a history of damaging 

earthquakes. This 

map shows large 

earthquakes that 

struck Hawaiÿi 

between 1823 and 

2010. Earthquakes 

in the State are 

primarily the 

result of active 

volcanism and 

related geologic 

processes.
3

MODIFIED MERCALLI INTENSITIES FOR THE 1868 GREAT KA‘U EARTHQUAKE

 On April 2, 1868, Hawaiÿi was struck by a powerful 

earthquake estimated to have a magnitude of 7.9. This map 

shows Modified Mercalli Intensities (MMI) inferred from 

eyewitness accounts of the Great Ka‘u earthquake. The 

earthquake produced tsunamis and landslides and caused 

stone buildings to collapse, killing 77 people. Original 

descriptions of the earthquake’s effects are provided for 

the MMI values shown on the map in white:

Keaïwa, MMI XII: Frame building thrown off foundation, 

racked and strained. People thrown upon the earth, 

where they were tossed up and down like balls. Duration 

estimated at 2 minutes. . . . People found it impossible to 

stand, had to sit on ground bracing with hands and feet 

to keep from falling over. . . .

Hilo, MMI VIII: Shook down almost every stone wall in 

town (even the foundation stones were moved), cracked 

basement of church in several places, and knocked 

down most brick chimneys. . . . The few stone buildings 

were ruined. Furniture, clocks, mirrors, and crockery was 

thrown down and broken. . . .

Kealakekua, MMI VIII: Strong kukui trees were bent 

backward and forward, stone houses thrown down, large 

landslides. Walls fell in all directions. . . .

Kohala, MMI VII: Ground waves seen, hard to keep balance, all mill engines stopped, very little damage, tall 

chimney of sugar mill did not fall.

Pacific Ocean

0 50 100 KILOMETERS

0 50 100 MILES

159° 157° 155°

21°

19°

INTENSITY

SHAKING

DAMAGE

Weak

None

Moderate

None

Light

Very light

Very strong

Moderate

Severe

Moderate/

Heavy

Violent

Heavy

Extreme

Very Heavy

Kauaÿi

Niÿihau Oÿahu

Moloka‘i

Lana‘i

Kaho‘olawe

Maui

Hawaiÿi

II-III IV V VII VIII IX X+

 Hilo VIII 

VIII Kealakekua

VIII

0 30 KILOMETERS

30 MILES 0

XII Keaïwa

156° 155°

20°

19°

VII VII Kohala

XII

Hawai‘i

VIII

VII

VIII

IX X

XI

Pacific Ocean

0 50 100 KILOMETERS

0 50 100 MILES

159° 157° 155°

21°

19°

INTENSITY

SHAKING

DAMAGE

Weak

None

Moderate

None

Light

Very light

Very strong

Moderate

Severe

Moderate/

Heavy

Violent

Heavy

Extreme

Very Heavy

Kauaÿi

Niÿihau Oÿahu

Moloka‘i

Lana‘i

Kaho‘olawe

Maui

Hawaiÿi

II-III IV V VII VIII IX X+

Naohulelua church was badly damaged by the 1868 Ka‘ u earthquake. The church, about 10 miles southwest of the quake’s epicenter, was never used again. The quake and its effects killed 

77 people in Hawaiÿi. (USGS photo by Paul Okubo.)
Earthquakes in Hawaiÿi are monitored by sensitive seismometers operated by the Hawai‘i Integrated 

Seismic Network (HISN). This map shows the distribution of previously existing and new or planned 

HISN seismic stations. The HISN is operated by the U.S. Geological Survey and the Pacific Tsunami 

Warning Center of the National Oceanic and Atmosphere Administration, in cooperation with State of 

Hawaii Civil Defense and other organizations.

coastal regions in Hawaiÿi, there is 

little time to react and respond to 

such earthquakes and their associated 

tsunamis. The tsunami generated by 

the 1975 quake reached populated 

areas along that coastline in seconds 

and Hilo Harbor in less than 20 minutes. Emergency managers in the 

State are concerned about tsunamis 

generated by quakes along the western coast of the Island of Hawaiÿi. 

It has been estimated that a tsunami 

from such a quake would reach Honolulu in 35 minutes.

Seismic Monitoring in Hawai ‘i

 There are three principal groups 

that monitor earthquakes in the State 

of Hawaii—the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory, the USGS National Strong 

Motion Project, and the Pacific Tsunami Warning Center (PTWC) of the 

National Oceanic and Atmospheric 

Administration (NOAA). Although 

each group has specific seismic 

monitoring objectives, improvements 

and upgrades to seismic instruments 

and data transmission technologies 

are presenting new opportunities for 

cooperatively operating seismic monitoring stations and integrating and coordinating data sharing, data handling, 

and earthquake reporting among these 

three groups. To meet the State’s seismic monitoring needs, the USGS and 

PTWC, in cooperation with the State of 

Hawaii Civil Defense and other organizations, have formed the Hawaiÿ i Integrated Seismic Network (HISN).

 Using seismic data streams from 

the HISN and other sources, the USGS 

automatically generates and posts on the 

Internet the time, location, and magnitude of quakes in Hawaiÿi. The USGS 

also automatically posts enhanced earthquake information products, including 

near real-time earthquake analysis and 

post-earthquake decision-making tools. 

The data and related products are shared 

among USGS and NOAA partners for 

enhanced hazard warning capabilities. 

The information products are intended 

to assist with effective post-earthquake 

response and recovery efforts. Through 

online questionnaires, the USGS also 

collects reports of earthquake effects 

and earthquake damage from the general public. As quickly after a significant 

earthquake as possible, these are automatically compiled and posted to the 

Web in the form of maps that reflect the 

intensity and extent of a quake’s impact.

The Earthquake Hazard in Hawai‘i

Because of Hawaiÿi’s history of damaging earthquakes and its active volcanism, 

it is not a question of “if” another devastating quake will strike but rather “when.” 

Hawaiÿi’s recorded history of damaging 

quakes provides helpful clues about the impact of future large earthquakes.

Probabilistic seismic hazard maps 

quantify the shaking hazard posed by 

future earthquakes. The USGS has produced a new generation of seismic hazard maps, recently developing and applying a consistent methodology across 

the entire United States. Important input 

and participation in arriving at the final products came from local expertise 

and experience. The National Seismic 

Hazard Maps are intended to reflect the 

best available science 

in earthquake hazards estimation. As 

of 2000, the USGS 

seismic hazards maps 

have been incorporated into all U.S. model 

building codes.

Seismic hazards 

maps show levels of 

4

N

Pacific Ocean

0 100 KILOMETERS

50 100 MILES

50

0

Broadband

Short period

Strong motion

 Existing stations

 New HISN stations

This road in Hawai‘i Volcanoes National Park, on 

the Island of Hawai‘i, was 

severely damaged by a 

magnitude 6.7 earthquake 

in November 1983. (USGS 

photo by T.J. Takahashi.)

Hawai‘i Integrated Seismic Network Stations
5

Sun Oct 15, 2006 17:07:48 GMT M 6.7 N19.88 W155.94 Depth: 38.9km ID: 2006 1015107

22 ̊

21.5 ̊

21 ̊

20.5 ̊

20 ̊

19.5 ̊

19 ̊

-158 ̊ -157 ̊ -156 ̊ -155 ̊

Map Veision 22 Proceeded Mon Jul 14.2003 08:52:39 AM MDT - NOT REVIEWED BY HUMAN 

USGS Peak Accel. Map (in%g) : Big Island Hawaii

EARTHQUAKE INFORMATION PRODUCTS RAPIDLY AVAILABLE ON THE INTERNET FROM THE USGS

USGS Community Internet Intensity Map (10 miles of Kailua Kona, Hawaii, Hawaii)

ID:twbh_06 07:07:48 HST OCT 15 2006 Mag=6.7 Latitude=19.88 Logitude=W155.94

22 ̊N

21 ̊N

20 ̊N

19 ̊N

158 ̊W 157 ̊W 156 ̊W 155 ̊W

Since the early 1990s, the magnitude and location of 

an earthquake have been available within minutes on the 

Internet, as a result of work by the U.S. Geological Survey 

(USGS) in cooperation with various regional seismic 

networks. Internet maps for recent and past quakes in 

Hawai‘i can be found through either the USGS Hawaiian 

Volcano Observatory (HVO) earthquakes Web page (http://

hvo.wr.usgs.gov/earthquakes/) or the USGS Earthquake 

Hazards Web site (http://earthquake.usgs.gov/).

The maps of Hawai‘i shown here were posted online 

following a magnitude 6.7 earthquake on October 15, 2006. 

The map above shows the location of the quake, along with 

the locations of aftershocks from the following 12 days, 

including one of magnitude 6.0 that occurred 7 minutes after 

the main shock.

The “ShakeMap” is an automatically generated 

computer map of the intensity of ground shaking in 

percent of g (g is the acceleration due to gravity or 980 

cm/sec/sec). Immediately following a quake, emergency 

managers can use this kind of map to quickly make 

response decisions. The quick, accurate, and important 

information provided in such ShakeMaps can aid in 

making the most effective use of emergency response 

resources.

The “Community Internet Intensity Map” was 

automatically created using information provided 

through an online questionnaire by 2,994 responders who 

experienced the earthquake. This shared information was 

then used to help create a map of shaking intensities and 

damage. Such maps contribute greatly in quickly assessing 

the scope of an earthquake emergency, even in areas 

lacking seismic instruments. In the United States, the 

“intensity” or effects of a quake are described using the 

Modified Mercalli Intensity (MMI) scale. The effects of a 

quake on the Earth’s surface, humans, objects of nature, 

and manmade structures are ranked on a scale of I through 

XII for the amount of shaking and the degree of damage; for 

example, I is not felt and XII is total destruction.

HVO Recent Earthquakes Web Page Shakemap

Community Internet Intensity Map
Seismic hazard maps for the State of Hawaii are available on the Web at http://gldims.cr.usgs.gov/

website/hishmp/viewer.htm. This map shows estimated peak horizontal ground acceleration with 

a 10% probability of exceedance in a 50-year interval. Ground acceleration values shown are expressed as a pecentage of g (g is the acceleration due to gravity or 980 cm/sec/sec).

earthquake ground motions computed 

for specified probability levels of exceedance, within specified timeframes. 

Often, these are stated as 10% probabilities that calculated levels of ground 

motion will be exceeded in a 50-year 

period. This is roughly equivalent to 

saying that these ground motions have 

a 1-in-475 chance of being exceeded in 

any given year.

Hawaiÿi seismic hazard maps, 

along with hazards maps for other 

regions, are available online at 

http://earthquake.usgs.gov/hazards/.

The online Hawaiÿi maps show both 2% 

and 10% exceedance probabilities for a 

50-year time interval. There is general 

agreement between the hazard maps 

and historical earthquake experience 

in Hawaiÿi. It is also worth noting that 

the entire southeast coast of the Island 

of Hawaiÿi is associated with 50-yearexceedance probabilities for ground 

motions of 100% g (g is the acceleration due to gravity or 980 cm/sec/sec), 

comparable to those associated with the 

maximum Modified Mercalli Intensity 

(MMI) values recorded from the 1868 

Kaÿu earthquake. As incorporated in 

updated seismic provisions of building codes, the hazards maps will help 

mitigate against future earthquake losses as 

Hawaiÿi’s built environment expands and 

evolves. Hawaiÿi seismic hazards maps are 

expected to be updated, taking advantage 

of additional data from Hawaiÿi’s damaging earthquakes of October 2006, as well 

as data derived from the HISN.

 The work of the USGS and its cooperators to monitor seismic activity in 

the State of Hawaii is providing crucial 

information needed to help better prepare 

emergency managers and residents of 

Hawaiÿi for the quakes that are certain 

to strike in the future. This effort is only 

part of the USGS hazards programs’ ongoing efforts to protect people’s lives and 

property, including in all of the volcanic 

regions of the United States.

Paul G. Okubo 

and

Jennifer S. Nakata

Edited by James W. Hendley II

Graphic design by Judy Weathers

For more information contact:

Paul G. Okubo

U. S. Geological Survey 

Hawaiian Volcano Observatory

P. O. Box 51

Hawai‘i National Park, HI 96718

Email: pokubo@usgs.gov

http://hvo.wr.usgs.gov/

or

USGS Volcano Hazards Program

http://volcanoes.usgs.gov/

USGS Earthquake Hazards Program

http://earthquake.usgs.gov

This Fact Sheet and any updates to 

it are 

available online at 

http://pubs.usgs.gov/fs/2011/3013/

6

This home in Kalapana collapsed as a result of a magnitude 6.1 earthquake that struck the Island of 

Hawai‘ i in June 1989. (USGS photo by J.D. Griggs.)