On April 5, 2024, a magnitude 4.8 earthquake struck Tewksbury, New Jersey, surprising many along the U.S. East Coast, particularly in New York City. This event prompted researchers to explore why damage was minimal near the epicenter despite diverse reports of shaking intensity. Studies revealed that the earthquake’s rupture direction played a significant role in directing shaking, which could inform future assessments of seismic risks in the region, highlighting its geological complexity and the need for further investigation.
The recent magnitude 4.8 earthquake in Tewksbury, New Jersey, caught the attention of numerous residents across the U.S. East Coast due to the surprising extent of its effects, particularly in New York City, which is approximately 40 miles away from the epicenter. While the earthquake, recorded on April 5, 2024, represents the largest seismic event in New Jersey since 1900, the minimal damage observed near the epicenter raised questions among researchers about the mechanics behind this phenomenon. In a study published in The Seismic Record, YoungHee Kim from Seoul National University, alongside collaborators at Columbia University, investigated the earthquake’s rupture direction to understand the distribution of reported shaking. Despite expectations for visible property damage—such as collapsed chimneys or cracked walls—the region around the epicenter showed no significant destruction. Local law enforcement reported the occurrence with unexpected calmness, contrasting sharply with the overwhelming reports from residents in New York City, where sensations of strong shaking were documented. The earthquake received more than 180,000 reports, the highest number ever recorded for a single event on the U.S. Geological Survey’s (USGS) “Did You Feel It?” platform. It is estimated that around 42 million people from Virginia to Maine experienced the tremors. Notably, reports from the southwest of the epicenter indicated “weak” shaking, while those northeast of it described “light to moderate” intensity. Models suggest that a magnitude 4.8 earthquake should typically produce far more powerful shaking within a radius of approximately six miles from the epicenter, prompting researchers to delve deeper into the characteristics of the rupture. Utilizing Lg waves, a type of seismic wave, researchers modeled the rupture’s behavior and determined that it had traveled toward the east-northeast and down along an east-dipping fault plane. This direction may have directed the earthquake’s energy away from the epicenter and towards the northeastern regions. Unlike typical earthquakes in the northeast U.S., which primarily occur along north-south trending faults, this event incorporated both thrust and strike-slip mechanisms along a newly identified north-northeast trending fault plane, highlighting its unique geological behavior. Some post-event investigations revealed minor damage, such as cracks in drywall and objects displaced from shelves, including the partial collapse of a historic structure, Taylor’s Mill. However, the precise fault responsible for this earthquake remains unidentified, and the Ramapo fault system appears inactive during this incident. The research offers valuable insights into identifying new earthquake sources and reassessing how tectonic stress is managed in the eastern United States. Seismologist Oliver Boyd emphasized that ongoing monitoring efforts through newly deployed seismometers will enhance understanding of crustal responses following seismic events and contribute to identifying potential seismic hazards across the region. This examination into the Tewksbury earthquake not only elucidates the shaking dynamics experienced by residents but also underscores the need for continued scientific inquiry to better comprehend earthquake risks in high-density urban areas.
The Tewksbury earthquake of April 5, 2024, marks a significant seismic event in New Jersey, particularly as it represents the first large-scale earthquake recorded in the state since 1900. The contrasting reports of shaking intensity across various distances from the epicenter—specifically, the discrepancy between minimal local damage and substantial shaking felt in metropolitan areas like New York City—presents an intriguing case for researchers. The investigation into the mechanics of the earthquake reveals broader geological implications for understanding fault dynamics and stress accommodation in a complex tectonic landscape.
In conclusion, the Tewksbury earthquake serves as a pivotal case study in understanding seismic mechanics and community responses to significant geological events. The research highlights the complexities surrounding the earthquake’s rupture direction and intensity reports, as well as the challenges of correlating seismic data with human experiences. The findings emphasize the necessity for ongoing monitoring and studies to enhance the predictive capabilities regarding seismic hazards in densely populated regions of the eastern United States.
Original Source: phys.org
