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At least 200,000 residential structures in New York City are at risk of seismic damage: NYT

2024-04-11T17:38:00-04:00

The five boroughs are home to more than 200,000 multifamily buildings made with un-reinforced brick and built from the mid-1800s to the 1930s, according to a city hazard plan. Many rowhouses across the city neighborhoods fall into this category. Such masonry cannot bend or flex during an earthquake and would instead break or crumble. A strong earthquake could cause some buildings of this type to collapse.

Last week’s 4.8 magnitude tri-state quake wasn’t nearly as strong as the (estimated) 5.5 magnitude incident that occurred on August 10, 1884, and would have caused $4.7 billion worth of damage to the modern city, according to the New York Times.

Experts have warned that the risk posed to New York City, even after its amended 1995 building codes called for “seismic gaps” between buildings, remains at least faintly plausible.

A 2002 Times article on earthquake preparedness in the Big Apple states the probability of a magnitude 6.0 or higher event occurring even once in the next 19,500 years is still "unlikely."

The USGS-documented sinking of buildings in Manhattan, meanwhile, is happening at a rate of between 1 to 2 millimeters per year.

New York City is actually sinking under the weight of its skyscrapers

2023-05-22T13:57:00-04:00

New York City is sinking under the weight of its skyscrapers, new research shows, which could put its population of more than 8 million people at an increased risk of coastal flooding. [...] Researchers estimated the weight of all of New York City’s buildings to be around 842 million tons. But to find the areas more vulnerable to sinking — or, as they call it in more scientific terms, “subsidence” — a key factor to consider was the type of soil beneath the buildings.

A new study authored by the United States Geological Survey (USGS) found the city to be sinking at a rate of between 1 to 2 millimeters per year, while parts of Lower Manhattan, Brooklyn, Queens, and Staten Island are subsiding at a rate of 2.75 millimeters. This comes at a time when planning officials, architects, and building owners are scrambling to adapt to the shrinking office market accelerated by the pandemic.

The increased flood risk, enhanced by construction densification, is particularly dangerous to coastal cities whose clay-rich soil causes “material softness and ability to flow under pressure,” according to the study.

CA seeks to allocate $10 million in state funds to new earthquake early warning system

2016-05-16T18:34:00-04:00

In a major reversal, Gov. Jerry Brown is seeking state funds for a fledgling earthquake early warning system for California, which would allow for a limited rollout of alerts by 2018...Though the governor’s proposed funding is a big step for the system, it does not come with ongoing funds to operate it. An earthquake early warning system for California alone will cost about $23 million to build and $12 million annually to operate[.]

USGS raises New York City's earthquake threat but lowers risk for tall towers

2014-07-18T17:31:00-04:00

Here is another reason to buy a mega-million-dollar apartment in a Manhattan high-rise: Earthquake forecast maps for New York City that a federal agency issued on Thursday indicate “a slightly lower hazard for tall buildings than previously thought.” The agency, the United States Geological Survey, tempered its latest quake prediction with a big caveat. “The tall buildings in Manhattan are not where you should be focusing [...]"

More insight in the geological survey and the updated U.S. National Seismic Hazard Maps at usgs.gov.