NEW YORK CITY GEOLOGICAL RISKS WITH RESPECT TO SEISMIC EVENTS (EARTHQUAKES)

In New Jersey and New York, the continued tectonic plate motion of perpetual slow drift of the North American Plate (NAP) hold residual compressive stresses on Mesozoic and Paleozoic fault systems. Focused seismicity occurs where of Ordovician Plutons in New York resist crustal drift due to pinning the crust to the asthenosphere (Herman, 2015, 2022, Sykes 2005).

On April 4, 2024 an earthquake, it’s epicenter located in Tewksbury Township New Jersey, of 4.8 as estimated by the USGS occurred. It was felt in the New York City area.

The purpose of our presentation is to describe earthquake vulnerability, engineering ,and architecture aspects of the New York metropolitan area. We will utilize the work of Askins Gateway Tunnel Project New York Analysis Report of 2022. We will examine USGS, New York, and local map data bases of subsurface rock cores, depth to bedrock, thickness of overburden, faulting, and seismic building codes, to evaluate risk assessment of select areas. Lateral and vertical variations of bedrock constitute seismic wave amplitude changes ( increases) traveling from rock to sediments. Vulnerability to liquification increases as well.

Northern Manhattan contains bedrock of metamorphic rocks, till and glacial deposits. Whereas the central and southern margins of the island are artificial landfill. Westchester, the Bronx, Northern Queens Brooklyn and Staten Island contain metamorphic Paleozoic and sedimentary rocks, Central and Southern Brooklyn-Queens are underlain by soft soils.

The critical and infrastructure and key resources (CIKR), defined by the Department of Homeland Security include water, infrastructure, and toxic releases that are 1) masonry, the most susceptible to destruction in Manhattan.2)The greatest concentration of healthcare and toxic release facilities which require operation to prevent exposure to the public are located in Southern Brooklyn-Queens and Western Long Island. The areas are underlain by significant sedimentary consolidated and unconsolidated deposits.