Cal Poly Threats and Hazards

Cal Poly has a moderate earthquake risk due to its proximity to several active fault zones. The most significant seismic threat to the area is posed by the San Andreas Fault, located about 40 miles to the east of the University, and the offshore Hosgri Fault that is closer to the Central California coast.

There are also situated near several smaller faults, including the Los Osos and Shoreline faults, which increase the likelihood of earthquake activity in the region.

The  United States Geological Survey  estimates that there is a 2% chance of a magnitude 6.0 or greater earthquake occurring within 30 miles of San Luis Obispo within the next 50 years. While this probability may seem low, it is important to note that even a moderate earthquake can cause significant damage and disrupt daily life in the area.

The Hosgri Fault is an offshore fault located along the Central Coast, extending for approximately 250 kilometers (155 miles) in a northwest-southeast direction, running parallel to the coastline and situated just a few miles offshore. The fault was first discovered in the early 1970s during the construction of the Diablo Canyon nuclear power plant.

The Hosgri Fault is considered a significant seismic hazard for the Central Coast region, including San Luis Obispo, due to its potential for generating earthquakes.  The fault is thought to be capable of producing earthquakes with magnitudes of up to 7.5 , although estimates may vary.

Additionally, the Shoreline Fault was discovered off the coast in the area of the Diablo Canyon Power Plant in 2008. The initial study of the fault - using conservative assumptions about the total length of the fault zone - indicates that a potential magnitude 6.5 strike-slip earthquake is possible. Follow up investigations were performed by PG&E in 2009, 2010, and more detailed studies are planned to more accurately refine the size and potential of the fault. (Report on the Analysis of the Shoreline Fault Zone, Central Coastal California, Report to the U.S. Nuclear Regulatory Commission, January 2011, PG&E)

The fault is part of a larger network of faults in the region, which include the San Andreas Fault and other lesser-known faults.

The  Diablo Canyon Nuclear Power Plant , located near Avila Beach in San Luis Obispo County, California, has been a critical source of electricity for the region since its inception. Operated by Pacific Gas and Electric Company (PG&E), the facility houses two pressurized water reactors, which together have a capacity of approximately 2,300 megawatts. This output supplies power to more than 1.7 million homes, contributing significantly to the energy needs of California.

However, the Diablo Canyon Nuclear Power Plant also presents potential risks and challenges, particularly in regard to its proximity to several active fault lines, including the Hosgri Fault and the San Andreas Fault. This situation raises concerns about the plant's vulnerability to seismic events and the potential consequences of an earthquake-triggered incident. To address these risks, the plant has been designed and constructed with rigorous safety measures and stringent structural standards. It has been engineered to withstand the ground motions expected from the strongest possible earthquakes predicted for the area. Additionally, the plant undergoes regular inspections and maintenance to ensure the ongoing safety and reliability of its operations.

Another risk associated with the Diablo Canyon Nuclear Power Plant - as with all nuclear power plants - is the potential for accidents that could lead to the release of radioactive materials. Although the likelihood of such events is extremely low, the consequences could be severe, with potential impacts on public health, the environment, and the local economy. The plant has multiple layers of safety systems, including containment structures and redundant cooling systems, designed to minimize the risk of accidents and protect the public in the event of an incident.

To prepare for nuclear incidents, the  County of San Luis Obispo , PG&E, the Federal Emergency Management Agency (FEMA), Nuclear Regulatory Commission, and the Environmental Protection Agency have developed detailed Standard Operating Procedures for their "Nuclear Power Plant Plan": depending on the magnitude and direction of a plume, an evacuation of "Protective Action Zone 8" may be ordered. Those who are in proximity to Cal Poly should go north on Highway 101 to the "Monitoring, Decontamination & Reception Center" at Camp Roberts. Alternatively, for Community Members in adjacent areas, you may be directed to evacuate south on Highway 101 to the Center at Nipomo High School.

Cal Poly experiences a variety of wind patterns due to its proximity to the Pacific Ocean and its location within the topography of the Central Coast.

Typically, coastal winds in this region follow a diurnal pattern, characterized by onshore winds (blowing from the ocean towards the land) during the day as the land heats up, and offshore winds (blowing from the land towards the ocean) at night as the land cools. These winds can vary in intensity depending on the season and specific weather patterns.

Wind can pose several threats, particularly when it is strong. It can cause structural damage to buildings, disrupt power lines leading to outages, and create hazardous conditions for high-profile vehicles on the roadways. On a university campus like Cal Poly, high winds could potentially disrupt outdoor activities, damage temporary structures, and even cause injury from flying debris.

In the context of wildland fires, wind is a critical factor that can significantly increase the spread and intensity of the fire; it supplies oxygen to the fire, dries out vegetation making it more flammable, and carries embers that can start new fires far from the original source. For example, the strong Santa Ana or Sundowner winds that occasionally affect this region can quickly turn a small brush fire into a massive wildfire.

In the case of nuclear accidents, wind can also play a complex role. Wind direction and speed are critical factors in the spread of radioactive materials following a nuclear incident. For instance, if a release of radioactive materials were to occur at the Diablo Canyon Power Plant, located about 12 miles west of San Luis Obispo, the prevailing wind patterns would significantly influence the distribution of radioactive particles, potentially impacting public safety and necessitating evacuation or shelter-in-place orders.

Cal Poly is no stranger to the risks posed by wildfires. Our region's Mediterranean climate, characterized by hot, dry summers and cool, wet winters, creates an environment in which wildfires can flourish. The combination of high temperatures, low humidity, strong winds, and an abundance of dry vegetation provides the perfect fuel for wildfires to ignite and spread rapidly. As climate change exacerbates these conditions, the potential for more frequent and intense wildfires in the area is a growing concern.

The landscape surrounding Cal Poly consists of a mix of forests, chaparral, grasslands, and residential areas, creating what is known as the wildland-urban interface (WUI). In the WUI, human habitation and development are in close proximity to fire-prone natural vegetation, increasing the risk of property damage and loss of life in the event of a wildfire. This risk is further compounded by limiting factors such as access for emergency vehicles, evacuation routes, and water supply in some remote areas.

To mitigate the risk of wildfires at Cal Poly, we utilize a multi-pronged approach with proactive measures such as vegetation management involving the removal or reduction of hazardous fuels (e.g., brush and grasses) to create defensible space around residential areas and Highway 1. Our local fire agencies also utilize prescribed burns to decrease fuel loads and restore the ecological balance in the region.

Widespread power outages can have a significant impact on communities, disrupting essential services, and posing risks to public safety. Whether planned or unplanned, these outages can occur due to various factors, including extreme weather events, natural disasters, equipment failure, or cyberattacks.

Understanding the threats posed by widespread power outages improves personal preparedness and ensuring the resilience of affected communities.

Public Safety Power Shutoff (PSPS) are planned events where precautionary measures are taken by utility companies to de-energize power lines during extreme weather conditions (e.g., high winds, extreme heat, ignitable fuel loads) in order to prevent wildfires. While these shutoffs serve a necessary purpose, they can also introduce hazards and threats to communities like San Luis Obispo and the broader California region.

Although Investor-Owned Utilities, such as PG&E, have dramatically improved their PSPS responses to narrow both scopes and durations, power disruptions can still pose severe threats and hazards. For Cal Poly, extended power outages can disrupt and negatively impacting students' learning and access to resources.

In the aggregate, power disruptions will impact essential services, including medical facilities, emergency services, water treatment plants, and transportation systems. This can hinder emergency response efforts and reduce access to necessary resources. Extended outages can have significant economic consequences for businesses and households, as they may result in lost productivity, spoiled food, and increased reliance on backup power sources, such as generators. Communication networks will be impacted, making it difficult for residents to receive critical information and updates during emergencies, which can further complicate emergency management efforts.

Extended outages will also disproportionately affect vulnerable populations, such as elderly individuals, people with disabilities, and those with medical conditions that require electrical equipment. These outages can lead to life-threatening situations for these individuals.

Rainfall and inclement weather are primarily seasonal phenomena in the area which boasts a mild Mediterranean climate. Generally the rainy season is from November through March. Typical rainfall amounts range from 20 to 25 inches over most of the campus area, however higher amounts can be expected in the foothills to the north of the main campus. Flooding generally occurs in response to heavy rainfall events when streams, rivers, and drainage channels overflow their banks. Even during moderately sized storms, flooding can also occur in low-lying areas that have poor drainage.

Many factors can increase the severity of floods including; fires in watershed areas, the placement of structures or fill material in flood-prone areas, and tidal influence in low lying coastal areas. Additionally, the construction of impervious surfaces such as roadways and rooftops will result in increased runoff. 

The 100-year flood, which is the standard used by most federal and state agencies, is used by the National Flood Insurance Program (NFIP) as the standard for floodplain management and to determine the need for flood insurance. Commonly misperceived, the following describes the FEMA definition of “100-year flood”:

The term "100-year flood" is misleading. It is not a flood that will occur once every 100 years. Rather, it is the flood elevation that has a one percent chance of being equaled or exceeded each year.

Thus, a 100-year flood could occur more than once in a relatively short period of time.

Flooding can cause temporary impacts to Cal Poly and its operations. While the campus core is essentially located on a hillside, Stenner and Brizzolara creek drainage systems (as seen in the 1995 Floods) can present varying hazards and may temporarily block access to and egress from the remote portions of the campus. 

While Cal Poly has a robust Emergency Management department and robust stakeholder participation in our Emergency Operations Center to coordinate divisional and unit-level responses to large disasters, safety is the responsibility of all Cal Poly Community Members.

We encourage all Community Member to review the contents of Cal Poly's Department of Emergency Management's (DEM)  Preparedness  webpage, and to, "Get a kit, make a plan, and be informed." For county-wide preparedness, please visit  Prepare SLO  to access a wealth of information.

In that spirit, we invite Community Members to review our in-depth " Cal Poly Hazard Profile Overview " and " Emergency Reference Guide ." We also encourage Community Members to review our Evacuation Map to familiarize themselves with our evacuation zones, campus emergency evacuation assembly points for specific buildings, car-less collection points, and evacuation routes.

For large-scale, regional evacuations, the County of San Luis Obispo has designated Cal Poly as " SLC-E219 ," which Community Members should be aware of, if a full-scale non-nuclear evacuation is ordered.

Cal Poly also maintains an Emergency Notification System named "PolyAlert." This is our primary tool for delivering critical emergency information to help ensure the safety of our community. PolyAlert can distribute emergency notifications through email, SMS text, and voice messages. Cal Poly email addresses are automatically enrolled in the PolyAlert system, but we highly encourage anyone with a Cal Poly Portal account to register their cell phone number to receive emergency alerts via text message in conjunction with the notification emails. Cal Poly students, faculty, staff, and auxiliary employees may register up to two phone numbers with the system on the “Personal Info” tab at   my.calpoly.edu. 

Typical alerts sent out on this system include warnings of potential hazards, emergency instructions, evacuation orders, and other critical life-safety notifications.

The County of San Luis Obispo utilizes  AlertSLO  to distribute county-wide notifications.

Cal Poly DEM also encourages Community Members to download the  MyShake  app that will provide early notification of earthquakes so that you will be more prepared to "Drop! Cover! Hold on!" in the event of an earthquake. We also encourage Community Members to participate annually in "The Great California Shakeout" drills.