RMS maintains a broad suite of catastrophe models to manage global earthquake risk. In my day-to-day work, I think about our current earthquake models and the scope of methodological advancements and new capabilities, and generally, I think globally.
But this past week, I was reminded – once again – of the earthquake risk in my own backyard. The RMS California headquarters is in the middle of Earthquake Country. The building is located approximately 5 miles from the Hayward Fault, which poses the greatest risk to the building’s site and our operations.
On October 21, 1868, a major earthquake on the Hayward Fault ruptured a section of the fault from the location of present-day Fremont to just north of Oakland.
Map of the San Francisco Bay Area counties in 2013, highlighting the 1868 rupture on the Hayward Fault, as well as the surrounding faults
Until the 1906 Great San Francisco Earthquake and Fire, the event on the Hayward Fault was known as the “Great San Francisco Earthquake” for the damage it caused to the major population center of San Francisco. According to U.S. census records, at the time of the 1868 earthquake, the total population of the Bay Area was about 260,000, with 150,000 people living in San Francisco. While it is difficult to know the exact amount of damage, the loss has been estimated at around $350,000 in 1868 dollars.
But what would be the impact to the highly populated Bay Area in 2013? The answer to this question requires an understanding of the people and property at risk from similar-sized earthquake 145 years later. RMS has explored the impacts of such an event in a report on the 145th anniversary of the Hayward Earthquake.
In 2013, the Hayward Fault transects the highly urbanized East Bay corridor of the San Francisco Bay Area. The Hayward Fault also crosses nearly every east-west connection that the Bay Area depends upon for water, electric, gas, and transportation. Close to 2.5 million people live on or near this fault zone, with over 7 million people at risk in the surrounding eight counties. This is over 25 times the population of the region at the time of the 1868 earthquake.
As it is assumed the next large earthquake on the Hayward Fault will likely fall within the range of M6.8 to M7.0, RMS explored six Hayward Fault scenarios developed by the USGS within the RMS U.S. Earthquake model. The RMS analysis shows that the overall economic loss to the $1.9 trillion of residential and commercial property at risk will likely range between $95 and $190 billion – beyond what has been experienced in recent California history. The distribution of losses varies significantly by scenario and is largely a function of directivity, the focusing of seismic energy in the direction of rupture.
In addition, the analysis shows that insured losses could fall between $11 and $26 billion, indicating that the massive cost of a Hayward Fault earthquake is expected to be directly borne by the residents and businesses in the area.
Range of economic and insured losses to the residential and commercial lines of business from six ground motion scenarios on the Hayward Fault in 2013
Much work has taken place over the past twenty years, however, to mitigate the impacts of a major Bay Area earthquake. Utilities and other infrastructure operators in the region have invested (or are investing) a total of about $20 billion to reduce the impact of future earthquakes. Most of these upgrades and retrofits will be completed by 2013 or 2014. In addition, many municipalities in the Bay Area have abandoned, retrofitted, or replaced public buildings with identified seismic risk.
While there is much to be applauded in the work that has already been undertaken, a catastrophic earthquake on the Hayward Fault would almost certainly have ripple effects throughout California and the United States. The San Francisco Bay Area has one of the highest concentrations of people and wealth in the U.S., and is recognized as a center of innovation in the country, due to the high density of venture capital firms in Silicon Valley, located along the southern part of the San Francisco Bay.
The San Francisco Bay Area’s particular vulnerability to future earthquakes drives a continuous need for dialogue between the public, government officials, business, and the insurance industry to explore new ways to manage the risk. RMS remains committed to facilitating dialogue among the various stakeholders and creating a culture of preparedness and resilience to better manage the earthquake risk in the San Francisco Bay Area.
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April 29, 2015
The Nepal Earthquake: What We Know So Far
Delhi, India also at high risk of earthquakes from the same collision zone
The earthquake in Nepal is very much a developing story. However, based on what we know, it’s shaping up to be the worst natural disaster this calendar year, particularly because Nepal is remote, economically challenged, and not resilient to an earthquake of this magnitude. The ground shaking appears to have been stronger in Kathmandu than the 1934 earthquake, possibly making it the largest we’ve seen in Nepal in almost a century.
As of April 29, Time Magazine reports that the death toll has crossed 5,000. It’s expected that casualties could surpasses 10,000, as rescue efforts continue.
While it is too early to draw substantial conclusions about the disaster—and the final casualty number—we are able to share some insight into the event and risk in the area:
Most large earthquakes in this region occur along the plate boundary collision zone:
In this region, the Indian continent dips beneath the Tibetan plateau. The Himalayan mountain chain and Everest are products of this collision zone, and the area at risk stretches from Assam and southern Bhutan to the east through Nepal to the mountains of northern Pakistan in the west. The magnitude 7.6 earthquake in Kashmir in 2005, which caused terrible damage to villages either side of the Pakistan-India border resulting in 86,000 fatalities, occurred along this plate boundary.
Nepal’s fragile economy will be affected: Nepal is one of the world’s poorest countries. The country’s main revenue sources are agriculture and tourism, including foreigners looking to scale Mount Everest. Reports indicate that the damage caused in recent days could substantially set back the economy of Nepal.
Kathmandu was hit hardest:The fault rupture of the Nepal earthquake extended eastward from its epicenter, passing underneath the city of Kathmandu.
Historic buildings throughout the city have been reduced to rubble. Darbar Square, which attracts millions of tourists annually and is vital for the Nepalese economy, has been razed. An overwhelming majority of homes in what’s known as the Gorkha district have been destroyed. Furthermore, many villages in the region needing assistance are in mountainous areas, making rescue efforts difficult.
Structures in Nepal were already at risk: The Nepalese population resides in unreinforced masonry structures that are highly vulnerable to earthquake ground shaking. Secondary hazards are of concern as well—including landslides and liquefaction.
Aid efforts are already helping to make Nepal more resilient
The widespread damage to infrastructure will be a significant setback for Nepal, which relies on agriculture and tourism. Organizations such as Build Change are already on site helping affected communities to start rebuilding their homes using disaster-resistant designs to increase the country’s resilience to future earthquakes. If you would like to support Build Change’s work, you can donate to their fund by clicking here.
Delhi, India is at high risk of earthquakes from the same collision zone
Between Gujarat and the Himalayas lies the mega-city of Delhi, which is exposed to significant earthquake risk from the surrounding plate movement.
Delhi’s seismic risk comes from both the Himalayan thrust zone, where the recent Nepal earthquake struck, and the transition zone between the stable continent and the active plate boundary—also the site of the 2001 M7.7 Gujarat earthquake, which resulted in 20,000 fatalities.
According to the Bureau of Indian Standards’ seismic zoning map, Delhi is within a “high seismic risk zone.” Combined with an older building stock made of unreinforced masonry and reinforced concrete, the city’s people, buildings, and economy are at significant risk.
Delhi is the northern industrial hub of India, with significant manufacturing exposure, including textiles, chemicals, fertilizers, and leather goods. Delhi’s service sector has also grown enormously in recent years, with expansion in information technology, telecommunications, and banking.
Projects piloting risk reduction in the city—through building retrofits or enhanced building inspections—have been underway and offer some degree of comfort that the seismic risk issues in Delhi are being acknowledged.
We will continue to monitor the situation in Nepal. If you have questions about the disaster please feel free to ask them in the comment section.…
Patricia leads the earthquake model product management team at RMS, responsible for the strategic management of the RMS suite of global catastrophic earthquake models, which assess earthquake risk in over 60 countries worldwide. Prior to this role, Dr. Grossi was the RMS research director, serving as a liaison between RMS and outside scientific research and academic institutions and managing the RMS research publications. Patricia has over 15 years of research experience in catastrophe modeling and risk management, and is a registered civil engineer in the state of California, with a BS in civil engineering and a PhD in engineering and risk management from the University of Pennsylvania, and an MS in structural engineering from Stanford University. In 2005, she co-edited and co-authored the book Catastrophe Modeling: A New Approach to Managing Risk.
