Seismica’s Post

Explore this notable article by EQS: Joint Inversion of Rayleigh Group and Phase Velocities for S-wave Velocity Structure of the 2021 MS6.0 Luxian Earthquake Source Area, China 🔷 Authors: Wei Xu, Pingping Wu, Dahu Li, Huili Guo, Qiyan Yang, Laiyu Lu, Zhifeng Ding 🔷 Keywords: Luxian earthquake, ambient noise tomography, S-wave velocity model, seismicity, seismogenic mechanism, joint inversion 🔷 Key points: • A fine three-dimensional (3-D) S-wave velocity model around the 2021 MS6.0 Luxian earthquake epicenter was constructed in this study, using the joint inversion of the Rayleigh phase and group velocity dispersions. • The 3-D S-wave velocity images show that the velocity varies significantly beneath the Yujiasi syncline as well as in the eastern and western branches of the Huayingshan fault belt, which is consistent with the geological structure. • The Luxian earthquake epicenter is located at the boundary between the high- and low-velocity S-wave zones, and injection fluids may affect low-velocity features. The seismogenic mechanism may therefore be related to the reactivation of pre-existing faults caused by hydraulic fracturing. Click here for the article: https://lnkd.in/gHiywdBP Click here to submit a paper: https://lnkd.in/e4DydcAM We hope this information will be helpful for your research. #EQS #Earthquake #Science #LuxianEarthquake #Seismicity #SeismogenicMechanism

Using 30 years of observations of the Gofar oceanic transform fault at the East Pacific Rise, Wei et al. bring us a model that simulates the best-observed earthquake cycles on Earth.    https://lnkd.in/d37TaiAm Large earthquakes repeatedly occur on the same fault over many cycles. Most earthquake cycles are hundreds of years long and therefore difficult to observe. A special kind of fault in the East Pacific Ocean has very short cycles (3-5 years), and we have a very good record of its seismic behavior for the past 30 years. In this paper, Wei et al. built a numerical model, which can simulate previous earthquakes and forecast future events. With this model, they can also calculate the surface deformation on the seafloor over time. New data can be collected and compared with different model results, and help constrain important parameters of the fault. #fault #eastpacificrise  #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #OpenAccess #OpenScience

Bolton et al. show that static stresses induced from a nearby ML 4.0 foreshock significantly perturbed the local stress state and could have triggered the 2020 Mentone Mw 4.8 earthquake in West Texas. https://lnkd.in/er32iBPH Understanding how earthquakes get started is a fundamental goal of earthquake science. If the early stages of an earthquake can be measured and characterized, then these details could in principle be integrated into models to help advance earthquake early warning systems and earthquake forecasting. Here, Bolton studies a sequence of 11 earthquakes leading up to the 2020 Mentone Mw 4.8 mainshock. Seismicity in this area is in large part induced from oil-gas operations, such as wastewater disposal and hydraulic fracturing. The sequence started with a ML 4.0 earthquake and was followed by a series of 10 smaller ML 1-2 earthquakes. The author shows that the initial ML 4.0 earthquake increased the stress state along the fault enough that it could have triggered several of the smaller ML 1-2 earthquakes as well as the mainshock itself.  At least 6/11 of earthquakes that followed the initial ML 4.0 are aftershocks as opposed to foreshocks to the mainshock. This work demonstrates that the nucleation process of the Mw 4.8 mainshock cannot easily be explained by simple end-member models. Instead, it is likely that a combination of mechanisms contributed to the nucleation and triggering of the 2020 Mw 4.8 Mentone mainshock. #Texas #mentone  #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #OpenAccess #OpenScience

Do large surface creep events link to deeper earthquakes? Huang et al.'s research on the Calaveras Fault suggests that structural controls are more important than surface creep transients in driving seismicity. Read more:  https://lnkd.in/ekfJdR-Q Huang et al. explored whether large surface creep events—where faults slip without causing earthquakes—trigger deeper seismic activity. Studying a 2021 creep event on the Calaveras Fault, They used AI-based tools and template matching techniques to detect small earthquakes. Their enhanced catalog revealed that, despite significant surface slip, earthquake patterns resembled historical activity, suggesting that fault structure, rather than transient stress changes linked to surface creep, likely controls seismicity. #Calaveras #fault #seismicity #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #OpenAccess #OpenScience

Here is our paper in the "The 9th International Conference on Seismology and Earthquake Engineering." In this paper, We demonstrate common patterns between two earthquake record components. The string-matching algorithm is used as the pattern recognition tool. The results indicate that the two components of an earthquake share hidden patterns which should be considered in generating artificial seismic records. #seismology #earthquake #structural_engineering #pattern_rcognition

Are these two earthquakes identical or not? Bonatis et al. examine the subtle differences within the recent aftershock sequences of two moderate (Mw5.3 and Mw5.4) earthquakes that occurred in the same area of the North Aegean Trough. Read now:  https://lnkd.in/dxhY_ef9 On September 26, 2020, and January 16, 2022, the North Aegean Sea area, just south of Chalkidiki peninsula, experienced two notable (Mw5.3 and Mw5.4) earthquakes. Given their proximity to each other in both time and space, and considering such moderate-sized earthquakes are rare in this area, it's essential to delve into their characteristics to grasp the underlying geological processes better. Bonatis et al. used data from nearby seismic stations to refine their earthquake catalog and conducted a detailed analysis of both aftershock sequences. Their findings suggest these earthquakes do not stem from the primary geological structure known as the North Aegean Trough, but from lesser-known faults nearby, which are often associated with such complex tectonic environments. #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #OpenAccess #OpenScience #greece

When you weigh the benefits of being far away from an earthquake, how important is being able to score it with precision? Click the link to find out! Thanks to U.S. Geological Survey (USGS) for their seismology resources.

The earthquake stress drop is a key parameter that represents the difference in stress levels on a fault before and after an earthquake. Calculating it is important to understand the energy released during earthquakes, understand the physics of the earthquake source and it is also an important ingredient in estimating ground motion. However, calculating it accurately is tricky, mainly due to problems of data quality and resolution, and the assumptions made in individual approaches which difficult comparison across studies. We are honored to contribute to the BSSA Special Section “Improving Measurements of Earthquake Source Parameters” with a study on source parameters of < 1500 micro-earthquakes in the Marmara region of the North Anatolian Fault. After strict quality selection, we applied and compared the spectral fitting approach and generalized inversion technique, two independent methodologies with different assumptions. Analyzing the dataset with consistent trends from both methods, we observe the smallest stress drops located on the portion of the fault that is partially creeping, while the largest stress drops are located on a fault jog within the locked part. The results and datasets are part of the supplementary materials of the paper. This study benefited from very constructive team work within different sections of the GFZ Potsdam and we learn a lot on the way! Feedback is always welcome. #earthquakes #earthquakephysics #Marmara #Deprem

A new study by Gossett et al. reveals significant correlations of earthquake magnitudes at interevent time and distance separations larger than previously thought. Read more:  https://lnkd.in/dzV6AXY9 Gossett et al. tackle one of the most important questions in seismology: does the magnitude of an earthquake event depend on the events that preceded it? This field and laboratory study examines how statistical correlations between magnitudes evolve with time and distance between seismic events. The findings suggest that magnitudes are correlated over a larger time and distance between seismic events than previously thought, indicating that magnitude correlations are not driven solely by the rupture of an identical fault patch. They also document different temporal and spatial decay patterns of the magnitude clustering signature. #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #OpenAccess #OpenScience

Comparing earthquake locations and magnitudes from different algorithms is not straightforward, especially for earthquake early warning. Jozinović et al. provide a minimum latency solution based on observed emerging waveform envelopes. Read more: https://lnkd.in/e5S43Twg Seismic networks often use multiple independent algorithms to characterize earthquakes for early warning and standard network practice. Jozinović et al. propose a goodness-of-fit measure that allows selecting the best solution (origin and magnitude pair) by comparing the observed and predicted velocity emerging waveform envelopes at a set of stations. Their method can be applied in real-time settings with minimum latency. They run tests that demonstrate that this method is very effective in selecting the optimal solution. Furthermore, they show that it also allows for the suppression of false alarms through the use of a goodness-of-fit threshold. #Seismology #EarthquakeScience #peerreviewed #DiamondOpenAccess #Earthquake #EEW #earlywarning #OpenAccess #OpenScience