The HayWired Earthquake Scenario—

We Can Outsmart Disaster

The HayWired earthquake scenario, led by 

the U.S. Geological Survey 

(USGS), anticipates the 

impacts of a hypothetical 

magnitude-7.0 earthquake 

on the Hayward Fault. The 

fault is along the east side of 

California’s San Francisco 

Bay and is among the most 

active and dangerous in 

the United States, because 

it runs through a densely 

urbanized and interconnected region. One way to 

learn about a large earthquake without experiencing 

it is to conduct a scientifically realistic scenario. The 

USGS and its partners 

in the HayWired Coalition and the HayWired 

Campaign are working to 

energize residents and businesses to engage in ongoing 

and new efforts to prepare 

the region for such a future 

earthquake.

Area 

of map

CALIF

 Lake 

Berryessa

San 

Pablo

 Bay

San Luis

Reservoir

PACIFIC 

OCEAN

SAN FRANCISCO BAY

 123 ̊ 122 ̊ 121 ̊

37 ̊

38 ̊

San Francisco

San Jose

Santa Rosa

Livermore

Fremont

Napa

Concord

Gilroy

Sacramento

Stockton

0

0 10 20 30 MILES

10 20 30 KILOMETERS

Base from U.S. Geological 

Survey 2009 National 

Elevation Dataset 

30-meter digital elevation 

model

EXPLANATION

Shaking and damage

Severe

Moderate

Weak

Oakland

Richmond

Hayward

This map of the San Francisco Bay region, California, shows simulated ground shaking caused by the 

hypothetical magnitude-7.0 mainshock of the HayWired earthquake scenario on the Hayward Fault. 

Red shows the most extreme ground shaking and where damage is the worst. The mainshock begins 

beneath the City of Oakland (star) and causes the Hayward Fault to rupture along about 52 miles of its 

length (thick black line). White lines are other major faults in the region.

The U.S. Geological Survey (USGS) is leading the HayWired 

earthquake scenario, which examines the likely effects of a large 

earthquake in California’s San Francisco Bay region. This hypothetical earthquake is only one of many plausible events that 

could be the region’s next big earthquake. The name HayWired 

speaks to the threat of earthquakes on the Hayward Fault and the 

vulnerabilities and strengths posed by the interconnectedness of 

the bay region’s people, utilities, roads, and economy—including 

the digital economy.

The HayWired scenario anticipates the impacts of a hypothetical magnitude (M ) 7.0 earthquake (mainshock) and its 

aftershocks on the Hayward Fault. The fault is along the east-bay 

side of San Francisco Bay and is among the most active and 

dangerous in the United States, because it runs through a densely 

urbanized and interconnected region with a population of more 

than 7 million people. A scientifically realistic scenario is one 

way to learn about a large earthquake without the people of the 

bay region actually living through a disaster.

The HayWired scenario was developed to guide residents of 

the bay region and policymakers in earthquake-risk reduction 

and resilience-building actions. Such actions taken now, before 

an earthquake, will help reduce injuries, damage and losses to 

buildings and infrastructure, and the number of people displaced 

from their homes, shortening the bay region’s recovery time 

when the next earthquake occurs.

The first HayWired earthquake scenario report was published 

in April 2017 (when released, these reports are made available 

at https://doi.org/10.3133/sir20175013). Since then, the USGS 

and its partners in the HayWired Coalition and the HayWired 

Campaign have been working to help residents, businesses, and 

local governments become better prepared for a future earthquake. Together, we can outsmart disaster!

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2018–3016

April 2018
A Certain Future of Large Earthquakes

The threat of a future earthquake as described in 

the HayWired scenario is real and could happen at 

any time. Scientists have documented a series of 

major prehistoric earthquakes on the Hayward Fault, 

approximately one every 100 to 220 years during the 

past 1,900 years. On average, for the past 12 major 

earthquakes on the fault, the interval between events 

has been about 150 years plus or minus 60 years. The 

last major earthquake on the Hayward Fault was a 

magnitude-6.8 earthquake in 1868—150 years ago . . .

(Photograph of 1868 Hayward Fault earthquake damage; courtesy of 

California State Library.)

Hazards from the Mainshock and Aftershocks

The epicenter of the hypothetical M 7.0 mainshock of the 

HayWired scenario is set on the Hayward Fault beneath the 

east-bay city of Oakland. In the scenario, the earthquake is 

assumed to occur at 4:18 p.m. on April 18, 2018, the anniversary of the M 7.8 1906 San Francisco earthquake. The mainshock ruptures the fault along its length for about 52 miles.

East-bay cities along the corridor from Richmond in the 

north to Fremont in the south—including Berkeley, Oakland, 

San Leandro, and Hayward—are hardest hit by violent 

ground shaking and sudden fault offset. This offset, movement of opposite sides of the fault relative to each other, is 

more than 6 feet in some places. Slow offset (afterslip) along 

the fault will continue for several months. Strong shaking 

is felt throughout the San Francisco Bay region. Shaking 

causes liquefaction (soils becoming liquid-like) in sandy, 

water-saturated soils along the margin of San Francisco Bay 

and along streams. It also causes landslides in the hills and 

mountains surrounding the bay, especially the hills of the 

east bay. Many aftershocks occur in the minutes to years 

following the mainshock, with the largest (M 6.4) occurring in 

Santa Clara County, near San Jose.

These hazards are described in detail in the HayWired 

scenario. They provide a basis for understanding building 

damages, water-supply disruptions, and fires that could result 

from a M 7.0 earthquake on the Hayward Fault.

5

5

80

80

505

280

680

580

101

101

San Francisco

San Jose

Sacramento

Santa Rosa

Monterey

Oakland

Base map from Esri, copyright 2014, used herein under license. 

Other data from U.S. Department of Commerce and 

U.S. Census Bureau

0

0 10 20 30 MILES

10 20 30 KILOMETERS

Magnitude 7.0

HayWired mainshock

2.5 − 2.9

3.0 − 3.9

4.0 − 4.9

5.0 − 5.9

6.0 − 6.9

Aftershock magnitude

Within 1 day

Time from mainshock

Within 1 week

Within 1 month

Within 1 year

Within 2 years (end of 

 modeling period)

123° 122°

38°

37°

EXPLANATION

PACIFIC 

OCEAN

This map of California’s San Francisco Bay region shows the hypothetical mainshock and aftershock sequence of the HayWired earthquake 

scenario on the Hayward Fault. In the scenario, aftershocks are modeled 

for 2 years after the mainshock—an innovation unique to HayWired. 

Early in the sequence, most aftershocks are concentrated near the 

Hayward Fault.

HayWired Coalition Partners

Alameda County Mayors’ Conference ●  Alameda County Sheriff's Office, Office of Emergency Services  ● American Red Cross ●  Art Center College of Des

Urban Area Security Initiative  ●  Bay Planning Coalition  ●  Boston University  ●  Business Recovery Managers Association  ●  California Business, Consume

Economic Development  ●  California Governor’s Office of Emergency Services  ●  California Independent Oil Marketers Association  ● California ISO ● C

of Oakland, Fire Department  ●  City of San Francisco, Department of Emergency Management  ●  City of Walnut Creek  ● Contra Costa County Mayors’ C

Consulting  ●  MMI Engineering  ●  Office of the Mayor, City and County of San Francisco  ●  Pacific Earthquake Engineering Research Center  ●  Pacific Ga

Earthquake Center  ●  SPA Risk LLC  ● SPUR ●  Strategic Economics  ●  Structural Engineers Association of Northern California  ●  The Brashear Group 

2
sign  ●  ARUP—Design and Engineering Consultants  ●  Association of Bay Area Governments—Metropolitan Transportation Commission  ● Aurecon ●  Bay Area Cen

r Services, and Housing Agency  ●  California Department of Public Health  ●  California Department of Transportation  ●  California Earthquake Authority  ●  Califor

California Public Utilities Commission ● California Resiliency Alliance ● California Seismic Safety Commission ●  Carnegie Melon University Silicon Valley  ● City and 

onference ●  Earthquake Country Alliance  ●  Earthquake Engineering Research Institute  ●  East Bay Municipal Utility District  ●  Federal Emergency Management Ag

as and Electric Company  ●  Palo Alto University  ●  Price School of Public Policy and Center for Risk and Economic Analysis of Terrorism Events, University of South

p LLC  ●  University of California Berkeley Seismological Laboratory  ●  University of Colorado Boulder  ●  University of Southern California  ●  U.S. Department of H

Building Damages

The Hayward Fault runs beneath the foundations of more 

than 300 buildings and other structures. One such building, 

the University of California Berkeley’s Memorial Stadium, is 

nearly bisected by the fault and has been retrofitted to withstand 

shaking and fault offset. Earthquake hazards from the fault are a 

threat to approximately 2 million buildings in the San Francisco 

Bay region.

For the HayWired scenario, property damage and direct business disruption losses are estimated to be more than $82 billion 

(in 2016 dollars). Most of the losses are attributable to shaking 

damage, liquefaction, and landslides (in that order). Eighty 

percent of shaking damage is caused by the M 7.0 mainshock, 

and the rest is due to aftershocks over a 2-year period.

Studies done for the HayWired scenario show that:

• Damage from the mainshock could render older steel-frame

high-rise office buildings and newer reinforced-concrete

residential buildings in downtown Oakland and San Francisco

unusable for as long as 10 months.

• Damage from the mainshock could displace about

77,000 households, and if other factors (such as utility 

outages) are included, the damage could displace as many as

152,000 households or approximately 411,000 people (based

on 2000 U.S. Census data).

• Even if all buildings in the bay region met current building

code, 0.4 percent could collapse, 5 percent could be unsafe to

occupy, and 19 percent could have restricted use.

• For only a small percentage cost increase, more resilient

buildings constructed to more stringent building codes could

allow 95 percent of the bay region’s population to remain in

their homes and workplaces following such an earthquake.

• When the public is consulted, they express a preference and

willingness to pay for greater building resilience. 

Casualties and Trapped People

For the HayWired scenario mainshock, estimates of casualties in the San Francisco Bay region include 800 deaths and 

18,000 nonfatal injuries from building and structural damage 

caused by ground shaking and liquefaction hazards. More than 

2,500 people in the region could require rescue from collapsed 

buildings, and more than 22,000 people could require rescue 

from stalled elevators. A study done for the scenario suggests 

that if an earthquake early warning system (ShakeAlert) were 

fully implemented for the bay region, and if people heeded alerts 

to promptly use “Drop, Cover, and Hold On” actions to protect 

themselves, as many as 1,500 of the 18,000 nonfatal injuries 

from the mainshock could be prevented.

Damages to Water Supply

As shown in recent large earthquakes worldwide, older, brittle 

pipes in water-distribution systems that supply homes and workplaces are vulnerable to damage. Restoration time depends on 

the restoration of other utilities and transportation routes and the 

availability of labor and material resources.

For the HayWired mainshock and aftershocks, a new waternetwork resilience model is used to estimate damage to and 

restoration times for two water networks in the San Francisco 

Bay region. Water-supply restoration times are also estimated for 

bay-region counties. Water-distribution systems in most of the 

bay region would be affected, but east-bay residents could lose 

water service for 6 weeks (some for as long as 6 months). Not 

only would normal water service be restricted, but the ability to 

suppress fires would also be reduced.

Santa Clara County

73 percent of service returned 

 in 7 days

Full service returned in 30 days

67 percent of service returned 

 in 7 days

Full service returned in 30 days

San Francisco County

35 percent of service returned 

 in 7 days

Full service returned in 90 days

San Mateo County

30 percent of service returned 

 in 7 days

Full service returned in 210 days

Alameda and Contra Costa Counties

Marin County

Full service returned 

in 7 days

San Francisco County

Full service returned 

in 7 days

Marin County

95 percent of service returned 

 in 7 days

Full service returned in 30 days

85 percent of service returned 

 in 7 days

Full service returned in 30 days

Santa Clara County

41 percent of service returned 

 in 7 days

Full service returned in 90 days

San Mateo County

47 percent of service returned 

 in 7 days

Full service returned in 210 days

Alameda and Contra Costa Counties

Current 

conditions 

With pipe 

replacement 

and fuel plan

Faster

restoration

of water

service

Prolonged

outages

This illustration shows water-service restoration times for counties in 

California’s San Francisco Bay region following the hypothetical magnitude-7.0 mainshock of the HayWired earthquake scenario. The image at 

left shows current conditions, and the image at right shows how waterservice restoration times could be substantially improved if water utilities 

replaced all brittle pipe in their systems and had a fuel-management plan 

and emergency generators with fuel at all pumping stations.

3
nter for Regional Disaster Resilience  ● Bay Area Council ●  Bay Area Rapid Transit Authority  ● Bay Area 

rnia Earthquake Clearinghouse  ●  California Geological Survey  ●  California Governor’s Office of Business and

 County of San Francisco ●  City of Berkeley  ● City of Fremont ●  City of Hayward  ●  City of Oakland  ● City 

gency  ●  Joint Venture Silicon Valley  ●  Laurie Johnson Consulting|Research  ● March Studios ●  Marin Economic

hern California  ●  Rockefeller Foundation—100 Resilient Cities  ●  San Jose Water Company  ● Southern California 

Homeland Security  ●  U.S. Geological Survey  ●  Wells Fargo

Fire Following Earthquake

Damage from the HayWired mainshock could trigger widespread fires in the San Francisco Bay region. During and soon 

after the mainshock, more than 400 gas- and electric-related fires 

could ignite. These fires could form conflagrations that might be 

as destructive as the powerful ground shaking of the mainshock. 

For example, the 1991 East Bay Hills firestorm killed 25 people, 

destroyed more than 3,000 homes and 450 apartment units, and 

burned more than 1,500 acres.

PACIFIC 

OCEAN

SAN

FRANCISCO

BAY

SAN

FRANCISCO

BAY

 122°30’ 122°

37°30’

38°

San

Francisco

San

Jose

Palo

Alto

SONOMA

COUNTY

NAPA

COUNTY

MARIN

COUNTY

CONTRA COSTA

COUNTY

ALAMEDA

COUNTY

SANTA

CLARA

COUNTY

SAN MATEO

COUNTY

SANTA CRUZ

COUNTY

SOLANA

COUNTY

Oakland

Data from C. Scawthorne, SPA Risk, LLC. Image compiled by M. Germeraad, Association of Bay Area 

Governments—Metropolitan Transportation Commission. Base image from Google Earth. County lines from 

Esri, copyright 2014, used herein under license

Fire losses, in millions

of dollars

EXPLANATION

1–10

10–50

50–100

100–500

More than 500

Hayward Fault

0 4 8 MILES

0 4 8 KILOMETERS

This map of California’s San Francisco Bay region shows areas burned 

as a result of fires caused by the hypothetical magnitude-7.0 mainshock 

of the HayWired earthquake scenario on the Hayward Fault. Warmer 

colors show areas with greater building losses. Effects are most severe 

near the Hayward Fault itself. These fires would result in a loss of 

residential and commercial building floor area, equivalent to more than 

52,000 single-family homes. The fires following the mainshock would 

be directly responsible for the loss of hundreds of lives, a total building replacement value of almost $16 billion, and total property losses 

approaching $30 billion (2016 dollars). Areas (polygons) shown are 

based on distance to the closest fire station.

In the HayWired scenario, residential and commercial 

building space equivalent to more than 52,000 single-family 

homes could burn as a result of more fires than can be fought 

by available firefighters and fire trucks. This is compounded 

by delays in response caused by communication outages, road 

closures and traffic, and water shortages. Such fires would 

kill hundreds of people, displace many more people from 

their homes, and cause additional property losses approaching 

$30 billion (in 2016 dollars), permanently changing the urban 

landscape of the bay region.

Seismic retrofitting of buildings would help to reduce fire 

ignitions. A workshop in 2014 with bay-region firefighters 

also highlighted the need to coordinate with water utilities, 

and a first-ever joint exercise of portable firefighting watersupply systems was also conducted as part of this HayWired 

Coalition activity.

Ongoing HayWired Topics

The HayWired scenario team is building on engineering 

analyses to further explore the societal consequences of a 

M 7.0 earthquake on the Hayward Fault. These societal issues 

include: 

• Impacts on information and communications technology 

(the “wired” in HayWired), especially given the relevance 

of Silicon Valley and the technology industry to the San 

Francisco Bay region’s and the Nation’s economies.

• Risks to infrastructure such as lifelines (highways, the Bay 

Area Rapid Transit Authority (BART) system, telecommunications, and electric power), including interactions 

among some systems and some estimates of damage and 

restoration times.

• Issues for community recovery, including population 

displacement, social vulnerability, and challenges such 

as housing, financing for rebuilding and other needs, and 

long-term recovery planning.

• Effects on jobs and the regional economy.

• Benefits of ShakeAlert earthquake early warning.

Investing in Earthquake Safety

Preparing for the next large, damaging earthquake in the 

San Francisco Bay region is not an insurmountable task. 

Local governments, regional agencies, infrastructure managers and utility-service providers, businesses, and residents 

have all taken enormous strides toward the goal of a resilient 

bay region. The last major Hayward Fault earthquake in 1868 

(M 6.8), along with the M 7.8 1906 San Francisco and the 

M 6.9 1989 Loma Prieta earthquakes, motivated residents of 

the bay region to implement seismic-safety measures throughout local communities.

Red line is Hayward Fault (Fremont 

is on the right), mapped by J. Lienkamper, USGS Data Series 177, 2006. 

Satellite imagery from USDA National 

Agricultural Imagery Program, 

compiled by J.L. Blair, USGS.

4
HayWired Uses Innovative Science

The HayWired scenario uses new, innovative science to 

better understand earthquake-related hazards and damages, 

as well as the benefits of risk-reduction actions. This science 

helps to:

Understand the Hazards

• More accurately predict ground-shaking intensity 

throughout the San Francisco Bay region using computer 

simulations of the way seismic waves travel.

• Pinpoint high-hazard areas using probabilities of 

landslide and soil liquefaction triggered by earthquake 

shaking.

• Develop a plan to communicate forecasts of a potential 

aftershock sequence after a large earthquake.

• Project possible continued surface offsets along a fault 

after a large earthquake.

Estimate Damage and Its Effects

• Estimate building damages from shaking, liquefaction, 

and landslides, as well as additional building damage 

due to ongoing aftershocks.

• Understand likely damage to water-supply networks and 

the vital ways in which lifelines (for example, utilities and 

roads) are interconnected and depend on one another.

• Provide insights into additional substantial damages from 

fire following earthquake.

• Predict how many people could be trapped under collapsed 

buildings or stuck in stalled elevators.

Analyze Benefits of Risk Reduction

• Show that if old, brittle pipes are replaced beforehand and 

repair crews have a back-up fuel plan, water service—

including drinking water—is restored faster after an 

earthquake.

• Demonstrate that enhancing building codes would help to 

reduce damage to new buildings during strong shaking.

• Better understand what the public expects from building 

codes, including that buildings will be useable after an 

earthquake.

• Emphasize that using ShakeAlert (https://www.shakealert.

org) earthquake early warning, combined with drills to 

practice “Drop, Cover, and Hold On,” could help prevent thousands of injuries and save lives in a powerful 

earthquake.

SOCIAL SCIENCES: Consequences 

ENGINEERING: Impacts

Landslides

and 

liquefaction

Ground shaking Mainshock, 

aftershocks, 

fault slip, and 

afterslip

Fire following

earthquake

Interdependencies Lifelines Structures

and codes

Earthquake

warning and

forecasting

Internet

economy

Communities

at risk

Environmental

health

EARTH SCIENCE: Hazards

Integrating across disciplines...

Silhouette images from http://All-Silhouettes.com

As illustrated in this diagram, the HayWired scenario is an interdisciplinary approach to understanding the effects of a powerful 

earthquake on a densely populated metropolitan region—California’s 

San Francisco Bay region. This scientifically realistic scenario builds 

on innovative earthquake science to examine engineering-related 

impacts to buildings and lifelines (utilities, communication lines, and 

roads), as well social and economic consequences. The insights 

gained from the scenario support the development of public policy that 

improves earthquake preparedness and emergency response not only 

in the bay region but also in other similarly earthquake-prone areas.

In the nearly 30 years since the Loma Prieta earthquake, 

the bay region has invested at least $25 billion, and possibly as 

much as $50 billion, in earthquake countermeasures (as reported 

in 2014 by the Association of Bay Area Governments and KQED 

Science; see chapter A of USGS Scientific Investigations Report 

2017–5013). Cities and utilities have invested tens of billions of 

dollars in seismic upgrades, retrofits, and replacements of older 

buildings and infrastructure. However, the HayWired earthquake 

scenario shows that there is still more to be done.

The HayWired Coalition

Since 2014, the USGS has worked on the HayWired scenario 

with representatives of organizations in the San Francisco Bay 

region. These have included 80 fire-department chiefs, dozens 

of emergency managers, and many representatives from utilities 

(water, gas, and electric), transportation agencies, and the information technology industry.

Starting in 2016, these and new partnerships were formalized under the banner of the HayWired Coalition (see bottom 

of pages 2, 3, and 4). The coalition is an alliance of more than 

50 agencies and businesses that aim to communicate the scenario 

to their constituents and address community concerns by: 

• Helping to build community capacity to respond to and 

recover from earthquakes,

• Advancing basic knowledge of earthquake risks,

• Informing actions to reduce earthquake risks, and

• Improving the communication and use of earthquake-hazard 

science in decision-making.

The HayWired Coalition has completed a year of engagement through workshops, meetings, trainings, and exercises. Key 

members of the coalition have used the earthquake scenario to:

5
• Explore applications of ground-motion simulations,

• Discuss the cost and performance trade-offs of more stringent 

building codes,

• Examine lifeline and infrastructure interdependencies,

• Provide the details and context for a toxic chemical plume, 

which could be released as a result of earthquake damage, for 

use in a response exercise with public health-care agencies 

and hospitals,

• Delve into impacts to and resilience of the information and 

communications technology sector and its users,

• Encourage businesses to develop and share earthquakerecovery plans that consider issues of workplace damage and 

usability and employee issues,

• Engage city governments to better understand and address 

earthquake hazards and damages with respect to recovery 

challenges, and

• Help regional governments and other organizations bolster 

their development polices to better address seismic resistance 

of homes, as well as housing availability and financing to 

rebuild after a disaster.

The HayWired Campaign

The HayWired Campaign is led by the California Seismic 

Safety Commission and the California Business, Consumer 

Services, and Housing Agency. The motto of the campaign 

is “together, we can outsmart disaster,” serving as a call to 

action for statewide engagement to strengthen business and 

lifeline resilience and to reduce risk from an earthquake like 

that modeled in the HayWired scenario. The Outsmart Disaster website (https://outsmartdisaster.com) provides actionable 

science for making informed decisions and is intended to help 

people and businesses reduce risk and improve their safety, 

security, and economic well-being before an earthquake.

The Alameda County Water District, California, has improved the reliability of their water system by replacing aging large-diameter water pipes 

where they cross the Hayward Fault. The pipes have been retrofitted to 

accommodate the slow, constant creep of the fault and sudden ground 

shaking from earthquakes. These pipelines are only one of many such 

examples of lifelines (such as utilities, communication lines, and roads) 

and other infrastructure that cross the fault. (Photograph courtesy of 

McGuire and Hester.)

Additional Resources

The HayWired Earthquake Scenario

(U.S. Geological Survey Scientific Investigations 

Report 2017–5013) 

https://doi.org/10.3133/sir20175013

The HayWired Scenario: An Urban Earthquake in a 

Connected World

(U.S. Geological Survey geonarrative with interactive 

content) 

https://www.usgs.gov/haywiredvol1geonarrative/

M6.8 October 21, 1868 Hayward Fault Earthquake

(U.S. Geological Survey website with links to additional 

resources) 

https://earthquake.usgs.gov/earthquakes/events/1868calif/

The Hayward Fault—Is It Due for a Repeat of the Powerful 

1868 Earthquake? 

(U.S. Geological Survey Fact Sheet 2008–3019) 

https://pubs.usgs.gov/fs/2008/3019/

Earthquake outlook for the San Francisco Bay region 

2014–2043

(U.S. Geological Survey Fact Sheet 2016–3020) 

https://doi.org/10.3133/fs20163020

Outsmart Disaster

(California Seismic Safety Commission and California Business, Consumer Services, and Housing Agency statewide 

campaign website) 

https://outsmartdisaster.com

Seven Steps to Earthquake Safety

(Earthquake Country Alliance website) 

https://www.earthquakecountry.org/sevensteps/

Kenneth W. Hudnut, Anne M. Wein, Dale A. Cox, 

Keith A. Porter, Laurie A. Johnson, Suzanne C. Perry, 

Jennifer L. Bruce, and Drew LaPointe

Edited by James W. Hendley II, Claire M. Landowski, 

Carolyn A. Donlin, and Monica E. Erdman

Layout by Suzanne C. Roberts

For more information contact:

1-888-ASK-USGS (1-888-275-8747)

https://earthquake.usgs.gov/

https://answers.usgs.gov/

https://www.facebook.com/USGeologicalSurvey

https://twitter.com/USGS

ISSN 2327-6916 (print) 

ISSN 2327-6932 (online) 

https://doi.org/10.3133/fs20183016

6