Investigation of Tewksbury Earthquake: Analyzing the Unusual Shaking Patterns

A magnitude 4.8 earthquake struck Tewksbury, New Jersey, on April 5, 2024, surprising many with strong shaking reported in distant areas like New York City while damage near the epicenter was minimal. Researchers noted that the direction of the earthquake’s rupture affected the experience of shaking, leading to the unusual pattern of reports. Significant insights regarding the mechanisms of the earthquake and its implications for future seismic hazard assessments are being pursued.

On April 5, 2024, a magnitude 4.8 earthquake struck Tewksbury, New Jersey, marking the largest seismic event recorded in the state since 1900. The earthquake drew widespread attention due to its surprising intensity; reports indicated strong shaking experienced as far away as New York City, approximately 40 miles from the epicenter, while the immediate area showed minimal damage. In a recent publication in “The Seismic Record,” researchers led by YoungHee Kim of Seoul National University examined why there was such a stark contrast in experiences of shaking among residents in distant locations. Among their observations, Kim and her colleague, Won-Young Kim, noted the lack of expected structural damage when they visited the area shortly after the earthquake. They wrote, “We expected some property damage—chimneys knocked down, walls cracked or plaster fallen to the ground—but there were no obvious signs of property damage.” In contrast, residents of New York City exhibited a pronounced reaction to the tremors, despite being much farther from the epicenter. The earthquake has since garnered over 180,000 felt reports, an unprecedented number for a single event reported by the U.S. Geological Survey (USGS). The study highlights the peculiar behavior of shaking across different regions, where those towards the southwest reported only weak shaking, while individuals northeast experienced light to moderate tremors. To investigate this anomaly, the researchers modeled the earthquake’s rupture, discovering it propagated towards the east-northeast along a fault plane that could explain the funneling of seismic waves. Typically, earthquakes in the eastern United States exhibit thrust faulting along north-south oriented faults, but the Tewksbury event appeared to involve a combination of thrust and strike-slip mechanisms along a north-northeast trending fault. This discovery is significant as it could indicate new earthquake sources and a need to reassess how stresses and strains are distributed in the eastern United States. Furthermore, Boyd and his colleagues documented some damage, such as minor structural issues and the partial collapse of a historic stone façade near Lebanon, New Jersey, although significant damage was limited. Currently, USGS has deployed additional seismometers in the area to monitor and understand post-earthquake dynamics better, with efforts ongoing to map aftershock sequences and approximate potential seismic hazards in the region. The ongoing research may yield insights into earthquake mechanisms and improve risk assessments across the eastern United States.

The 2024 Tewksbury earthquake is notable because it was the most powerful earthquake in New Jersey within over a century and was felt across a large area of the U.S. East Coast. Such seismic events are of particular interest to researchers due to the relatively low frequency of significant earthquakes in this region compared to areas along the West Coast. The research presented in “The Seismic Record” looks to clarify how the dynamics of an earthquake’s rupture can influence the perception of shaking and substantiate claims of felt intensity across vast distances, a subject of considerable relevance in seismology.

In conclusion, the April 2024 Tewksbury, New Jersey earthquake prompted a comprehensive analysis of seismic activity, particularly its surprising impact on distant locations. By exploring the direction and nature of the earthquake’s rupture, researchers have begun to unravel the complexities of seismic wave propagation and its implications for understanding potential hazards across the eastern United States. This research not only adds depth to our understanding of the Tewksbury event but also signals a need to reassess the geological dynamics of the region in light of new findings.

Original Source: phys.org