Analysis of Tewksbury Earthquake Provides Insights into Seismic Activity in New Jersey

A magnitude 4.8 earthquake struck Tewksbury, New Jersey on April 5, 2024, felt across the East Coast. Despite minimal damage near the epicenter, strong shaking was reported as far as New York City. Researchers analyzed the rupture dynamics to explain this phenomenon, concluding that the earthquake’s intensity was funneled away from the epicenter due to its east-northeast propagation. The study has implications for understanding seismic risks in the northeastern U.S.

On April 5, 2024, a notable magnitude 4.8 earthquake struck Tewksbury, New Jersey, marking the most significant instrumentally recorded seismic event in the state since 1900. The tremors were felt across a vast region of the U.S. East Coast, prompting over 180,000 reports via the U.S. Geological Survey’s “Did You Feel It?” platform, making it the highest number of felt reports for any single earthquake in the program’s history. Surprisingly, while residents in New York City, approximately 40 miles away, reported strong shaking, damage near the epicenter was minimal. Research led by YoungHee Kim and her colleagues from Seoul National University and Columbia University’s Lamont-Doherty Earth Observatory investigated the earthquake’s rupture mechanism to explain these discrepancies in shaking reports. Examining aftershocks and seismic waves, they proposed that the earthquake’s rupture propagated predominantly toward the east-northeast, utilizing a unique fault mechanism combining thrust and strike-slip characteristics. This pattern may have funneled seismic energy away from the Tewksbury area, redirecting stronger tremors towards locations further northeast. In a subsequent analysis, USGS seismologist Oliver Boyd confirmed that the earthquake was felt by an estimated 42 million individuals from Virginia to Maine, and he highlighted that the eastern U.S. typically experiences seismic events along existing fault lines. The geological investigation remains ongoing to determine the exact fault responsible for this earthquake, but initial assessments suggest that the Ramapo fault system was not implicated. This research carries broader implications for understanding earthquake sources and mechanisms in the eastern United States. The deployment of additional seismometers in the affected region aims to further illuminate characteristics of seismic activity and improve hazard assessments in the future.

The Tewksbury earthquake of 2024 was unprecedented for New Jersey, generating widespread public concern and extensive data collection efforts. Given its magnitude and the wide reach of its effects, researchers have engaged in analyzing its rupture dynamics to explain unusual shaking patterns observed, particularly in areas significantly distanced from the epicenter such as New York City. Previous models of earthquake intensity have primarily focused on the impacts in closer proximity to the epicenter; however, this earthquake presented discrepancies that warranted a reassessment of existing theories regarding seismic waves and fault mechanics in the northeastern United States. Understanding the rupture direction and type may allow scientists to refine their methodologies concerning seismic hazard evaluations.

The analysis of the Tewksbury earthquake indicates that the unique characteristics of its rupture may have significantly influenced the observed shaking intensity over wide distances. The study suggests a novel fault mechanism in the region, potentially reshaping our understanding of seismic risks on the eastern seaboard. These findings highlight the necessity of continuous monitoring and investigation into the complex behaviors of earthquakes in the eastern U.S. to better prepare for future seismic events.

Original Source: phys.org