Potential Earthquake Research Articles

Geospatial Information Analysis Based on Numerical Modelling of Tsunami Inundation in Coastal Area of Temon District, Kulon Progo Regency

Abstract The southern coastal area of Java Island is a subduction area confluence of the Eurasian Plate and the Indo-Australian Plate. The southern area of Temon District, Kulon Progo Regency includes the Central Java-East Java megathrust area. Megathrust Central Java-East Java has a maximum earthquake potential of 8.9 Mw which has the potential to cause a tsunami disaster. The built-up land area in Temon District has a potential threat from the danger of tsunami inundation. The purpose of this study is to (1) analyze the danger of tsunami inundation in Temon District and (2) determine the area of built-up land affected by tsunami inundation. The method used in this study is descriptive quantitative-qualitative. TUNAMI-N3 was used in numerical modelling to determine tsunami inundation hazards and Google Earth Engine was used in analyze built-up land in Temon District. The results of tsunami inundation hazard treatment and built-up land areas were analyze using ArcGIS 10.8 to determine built-up land affected by the potential tsunami inundation hazard. The results showed that the tsunami generated from the earthquake scenario with a magnitude of Mw 8.9 had a maximum height of 19.86 meters with an average travel time of 33 minutes to reach the coastal area of Temon District. Temon District affected by tsunami inundation hazard has a tsunami area of 2.47 km2 with details of a low tsunami danger level of 0.67 km2, medium tsunami danger of 0.95 km2 and high tsunami danger of 0.85 km2. The maximum height of the tsunami inundation bath is 6.54 meters. Temon District has a built-up land area of 14.308 km2. Built-up land affected by tsunami inundation is 0.55 km2 with details of 0.14 km2 at low danger of tsunami inundation, 0.20 km2 at medium danger of tsunami inundation and 0.21 km2 at high tsunami inundation hazard.

Uttarakhand State Earthquake Early Warning System: A Case Study of the Himalayan Environment.

The increased seismic activity observed in the Himalayas, coupled with the expanding urbanization of the surrounding areas in northern India, poses significant risks to both human lives and property. Developing an earthquake early warning system in the region could help in alleviating these risks, especially benefiting cities and towns in mountainous and foothill regions close to potential earthquake epicenters. To address this concern, the government and the science and engineering community collaborated to establish the Uttarakhand State Earthquake Early Warning System (UEEWS). The government of Uttarakhand successfully launched this full-fledged operational system to the public on 4 August 2021. The UEEWS includes an array of 170 accelerometers installed in the seismogenic areas of the Uttarakhand. Ground motion data from these sensors are transmitted to the central server through the dedicated private telecommunication network 24 hours a day, seven days a week. This system is designed to issue warnings for moderate to high-magnitude earthquakes via a mobile app freely available for smartphone users and by blowing sirens units installed in the buildings earmarked by the government. The UEEWS has successfully issued alerts for light earthquakes that have occurred in the instrumented region and warnings for moderate earthquakes that have triggered in the vicinity of the instrumented area. This paper provides an overview of the design of the UEEWS, details of instrumentation, adaptation of attributes and their relation to earthquake parameters, operational flow of the system, and information about dissemination of warnings to the public.

Applying Machine Learning to Earthquake Engineering: A Scientometric Analysis of World Research

Machine Learning (ML) has developed rapidly in recent years, achieving exciting advancements in applications such as data mining, computer vision, natural language processing, data feature extraction, and prediction. ML methods are increasingly being utilized in various aspects of seismic engineering, such as predicting the performance of various construction materials, monitoring the health of building structures or components, forecasting their seismic resistance, predicting potential earthquakes or aftershocks, and evaluating the residual performance of post-earthquake damaged buildings. This study conducts a scientometric-based review on the application of machine learning in seismic engineering. The Scopus database was selected for the data search and retrieval. During the data analysis, the sources of publications relevant to machine learning applications in seismic engineering, relevant keywords, influential authors based on publication count, and significant articles based on citation count were identified. The sources, keywords, and publications in the literature were analyzed and scientifically visualized using the VOSviewer software tool. The analysis results will help researchers understand the trending and latest research topics in the related field, facilitate collaboration among researchers, and promote the exchange of innovative ideas and methods.

Improved medium-to-short-term earthquake predictions in China in 2022

Every year, China should determine annual seismic hazard regions for earthquakes of magnitude 5.0 and above in Mainland China in the next year. Meanwhile, the short-term earthquake potential in each seismic hazard region is evaluated by monthly analyzing geophysical observations in the same neighborhood and identifying anomalies therein. In 2022, China improved the strategies for these medium-to-short-term earthquake predictions. The annual seismic hazard regions are produced with the optimal methods selected by rigorous tests whose predictions are integrated through the Bayesian formula. And in short-term earthquake potential evaluation, in addition to tracking crucial anomalies, China pays attention to the changes in the number of observed anomalies. The practice in 2022 shows that more than 80% of earthquakes of magnitude 5.0 and above in Mainland China occurred in annual seismic hazard regions. Besides, the largest (M s 6.9 Menyuan, Qinghai) and the most disastrous (M s 6.8 Luding, Sichuan) earthquakes were predicted in both annual and short terms. Some crucial anomalies were observed before these two earthquakes, whose evolutions correlate well with the earthquake time and location. The statistics of the near-field geophysical observations indicate that, prior to the mainshock, the number of anomalies increased significantly and migrated toward the epicenter.

Possible Maximum Earthquake Tsunami Along the South Coast of China Inferred From GPS‐Derived Surface Velocities

AbstractThis study aims to assess the tsunami hazard of the maximum possible earthquake along the south coast of China. GPS‐derived surface velocities around the Manila Trench have been used to clarify the active tectonics and estimate the seismic potential of Manila subduction, where catastrophic tsunamis may originate and cause devastating damage to the surrounding area of the South China Sea. Based on the maximum potential earthquake magnitude estimated from the accumulated seismic moment, more than 100,000 possible tsunami scenarios with varying epicenters have been simulated considering the slip heterogeneity. The impact of several uncertain parameters including the release period and release ratio of accumulated seismic moment are investigated, as well as some assumptions in the model of tsunami generation. Although different release conditions for accumulated seismic moment result in a significant impact on the value of tsunami height, similar trend in spatial distribution has been shown. The results show that the tsunami wave height along the south coast of China has an increasing trend from west to east, with the maximum tsunami wave height exceeding 10 m corresponding to the potential earthquake Mw = 9.1 with a 1,000‐year release period. The impact of fault slip heterogeneity on tsunami wave height is significant. Compared to uniform slip, considering stochastic slip will increase the average tsunami wave height by about 15%. Considering locking distribution will increase the average tsunami wave height by about 20%–30% and also increase the maximum tsunami wave height by about 60%–70%.

The earthquake probabilities of the Liupanshan fault zone based on the Coulomb stress and friction constitutive law

As the forefront of the northeastern margin of the Tibetan Plateau, the Liupanshan area is subjected to significant Cenozoic deformation. Considering the background of historical earthquakes and the current seismic activity, the Liupanshan fault poses a risk of strong earthquakes. This paper analyzes the evolution of Coulomb stress induced by the coseismic and postseismic viscoelastic deformation of six historical strong earthquakes that occurred around the Liupanshan area since the twentieth century. Additionally, based on the disturbance in Coulomb stress and the background seismicity rate, the probability of earthquake occurrence is quantitatively evaluated using the frictional constitutive law. The results indicate that northern section of the Liupanshan fault has higher earthquake potential than the southern section, warranting close attention. These findings serve as a reference for medium- and long-term earthquake forecast and risk assessment in the vicinity of the Liupanshan fault.

Radon concentration in seawater as a geochemical indicator of submarine fault activity in the Yatsushiro Sea, Japan

This study examined the relationship between radon (222Rn) concentrations in seawater and crustal activity in the Yatsushiro Sea by investigating the submarine fault zone situated at the southern end of the Futagawa–Hinagu fault zone, activated by the 2016 Kumamoto earthquake (M7.3). We conducted an analysis of 222Rn concentration in samples of bottom water just above the seafloor and pore water in sediments, utilizing multiple and piston cores from the Hakuho Maru Expedition KH18-3. The findings revealed significantly elevated 222Rn concentrations in the central sites of the Yatsushiro Sea, coinciding with a high-stress field exhibiting dense active faults. Seismicity analysis revealed heightened moment release and a low b-value post the 2016 Kumamoto earthquake, indicative of increased seismic activity and the potential for substantial earthquakes in the Yatsushiro Sea vicinity. Our results indicate that heightened concentrations of 222Rn in seawater can serve as an effective tracer for identifying and estimating submarine fault activities. Moreover, our research highlights the utility of 222Rn concentrations in detecting active submarine faults and assessing their activity. It contributes to a comprehensive understanding of the potential for significant earthquakes in the Yatsushiro Sea in the future.

Tsunami deposits highlight high-magnitude earthquake potential in the Guerrero seismic gap Mexico

Globally, the largest tsunamigenic earthquakes have occurred along subduction zones. Devastating events exceeding magnitude 9, such as those in Chile, Sumatra, and Japan, struck in regions lacking instrumental records of similar events. Despite the absence of such events along the 1000-kilometer-long Mexican subduction zone, historical and geologic evidence suggests the occurrence of a magnitude 8.6 tsunamigenic earthquake. However, the Guerrero seismic gap has not experienced a high-magnitude earthquake in over 100 years. Here we present results on analyses of sediment grain size, geochemistry, microfossils, magnetic properties, and radiometric and optical stimulated luminescence dating conducted along the Guerrero coast. We provide evidence of a 2000-year history of large tsunamis triggered by potentially large earthquakes. Numerical modeling supports our findings, indicating a magnitude >8 event around the year 1300 in the Guerrero seismic gap. This evidence underscores the importance of assessing earthquake and tsunami potential using long-term evidence and instrumental observations along subduction zones globally.

VLF Signal Noise Reduction during Intense Seismic Activity: First Study of Wave Excitations and Attenuations in the VLF Signal Amplitude

This study is a continuation of pilot research on the relationships between seismic activity and changes in very low frequency (VLF) signals starting a few minutes or a few dozen minutes before an earthquake. These changes are recorded in the time and frequency domains and their duration can be influenced not only by the strongest earthquake but also by others that occur in a short time interval. This suggests that there are differences in these changes in cases of individual earthquakes and during the period of intense seismic activity (PISA). In a recent study, they were validated in the time domain by comparing the amplitude noise reductions during the PISA and before earthquakes that occurred in the analysed periods without intense seismic activity (PWISA). Here, we analyse the changes in the VLF signal amplitude in the frequency domain during the PISA and their differences are compared to the previously investigated relevant changes during PWISA. We observe the signal emitted by the ICV transmitter in Italy and received in Serbia from 26 October to 2 November 2016 when 907 earthquakes occurred in Central Italy. The study is based on analyses of the Fourier amplitude AF obtained by applying the fast Fourier transform (FFT) to the values of the ICV signal amplitude sampled at 0.1 s. The obtained results confirm the existence of one of the potential earthquake precursors observed during PWISA: significantly smaller values of AF for small wave periods (they can be smaller than 10−3 dB) than under quiet conditions (the expected values are larger than 10−2 dB). Exceptions were the values of AF for wave periods between 1.4 s and 2 s from a few days before the observed PISA to almost the end of that period. They were similar or higher than the values expected under quiet conditions. The mentioned decrease lasted throughout the observed longer period from 10 October to 10 November, with occasional normalisation. It was many times longer than the decreases in AF around the considered earthquakes during PWISA, which lasted up to several hours. In addition, no significant wave excitations were recorded at discrete small values of the wave periods during the PISA, as was the case for earthquakes during PWISA. These differences indicate the potential possibility of predicting the PISA if the corresponding earthquake precursors are recorded. Due to their importance for potential warning systems, they should be analysed in more detail in future statistical studies.

Association of land surface temperature anomalies from GOES/ABI, MSG/SEVIRI, and Himawari-8/AHI with land earthquakes between 2010 and 2021

Every year, earthquakes cause numerous casualties and billions of dollars in economic damages, and so far, it is impossible to predict them. Many researchers have studied the land surface temperature (LST) anomalies as promising potential earthquake precursors. In this work, more than 30,000 land earthquakes with a Magnitude (Mw) larger than 4 have been studied from 2010 to 2021. Global LST nighttime (0–6 am) data from Meteosat Second Generation (MSG), Himawari-8, and the Geostationary Operational Environmental Satellite (GOES) satellites have been used to evaluate the LST anomalies in the zones affected by earthquakes with spatial resolutions of 1, 2, and 4 km, respectively. The time series moving standard deviation (STD) and Interquartile (IQT) have been used to estimate the LST anomalies. The Confusion Matrix (CM), the receiver operating curve (ROC), and some other figures of merit are computed to assess the goodness of positive LST anomalies and detection thresholds as potential proxies of earthquake occurrence. A positive LST anomaly is typically observed a few days [1–7 d] before the earthquake’s occurrence, followed by a negative LST anomaly afterwards [1–3 d].

An Updated Fault Coupling Model Along Major Block‐Bounding Faults on the Eastern and Northeastern Tibetan Plateau From a Stress‐Constrained Inversion of GPS and InSAR Data

AbstractLarge block‐bounding faults on the Tibetan plateau are significant geological structures that accommodate tectonic movements and accumulate stress, leading to large earthquakes. Quantifying the interseismic slip deficit rate helps to better assess the earthquake potential. We combine available InSAR (2015–2020) and interseismic GPS data to determine fault coupling along 14 major block‐bounding faults. Spatially dense InSAR measurements remarkably improve the resolution of the coupling model. Combined with a GPS‐constrained block model, we examine the performance of the inversion approach with the stress constraint and the common Laplacian smoothing based on both synthetic tests and real data. We suggest that, for continental strike‐slip faults, adding the stress constraint can mitigate unphysical coupling distributions due to unreasonable assumptions or modeling artifacts, reducing the model uncertainty and improving the accuracy of the coupling model. This is particularly useful for segments featured by a highly heterogeneous distribution of coupling along the transition zone from locking to creeping region, partially‐coupling segment, and junction zone between main and subsidiary faults. We present a large‐scale fault coupling map along the major block‐bounding faults on the northeastern and eastern Tibetan plateau, highlighting the distinct degrees of fault coupling and lateral variations. The collage of coupling maps along different faults demonstrates the kinematic features over a broad time scale during earthquake cycles ranging from early to late interseismic phases, such as the segments ruptured during the 2001 Kokoxili earthquake and the 1920 Haiyuan earthquake.

Enhancing Disaster Preparedness for Junior High School Students at SMPN 24 Padang City Using Virtual Reality Method

Indonesia frequently experiences earthquakes, resulting in significant financial losses and casualties, especially in Padang. A major factor contributing to the high number of victims is the general public's lack of knowledge and preparedness for such disasters. Teenagers, including middle school students, are particularly vulnerable. Consequently, at SMPN 24 in Padang, virtual reality (VR) technology has been introduced to educate students about disaster preparedness. This simulation provided a realistic learning experience, allowing students to practice for emergencies without endangering themselves. At SMPN 24 in Padang, 32 students underwent an earthquake simulation using the VR approach. The results indicated an enhanced understanding of disaster preparedness among the students, with the median comprehension score rising from 59.00 to 60.50. Evaluations suggest that VR technology effectively increases students' disaster awareness and readiness. In summary, thanks to the virtual reality (VR) training, students at SMPN 24 in Padang feel better equipped to face potential earthquake disasters.

Stress disturbance around Xianshuihe fault zone in the eastern Qinghai–Tibet Plateau and implication for fault stability

The Xianshuihe fault zone in the eastern Qinghai–Tibetan Plateau is an important active tectonic boundary. Understanding its stress state is important for characterizing the dynamic evolution of the Qinghai–Tibet Plateau and the mechanism of the frequent occurrence of large earthquakes. Using 30 years of in-situ stress data from the Xianshuihe active fault zone, we statistically analyzed the spatial distribution characteristics of the stress in the region. The study area is generally characterized by a strike-slip stress field. Nevertheless, the stress state is vulnerable to topography and shows high spatial variation near the Earth’s surface at a depth of 0–400 m. The local stress near the fault zone varies from the far-field stress. The orientations of the maximum horizontal principal stress possess an elliptical shape around the fault zone, while its magnitudes become hump-like as the distance increases from the fault. The large difference in properties between the fault zone and its adjacent rocks contributes to the differentiation of the direction of the local stress field near the fault. The results allow us to formulate a preliminary hypothesis that a rigid lateral extrusion model may control the nonuniformity of the local stress field in the Xianshuihe fault zone and preferentially interpret the tectonic uplift of the southeastern margin of the Qinghai–Tibet Plateau. Further, the stress accumulation in the shallow crustal regions of the Xianshuihe fault zone is relatively high, indicating that some segments of the fault zone are critically unstable. Kangding area (the Zheduotang segment and the Yalahe segment) and Luhuo segment hold relatively high potential for large earthquakes. The results of this study are of great significance for revealing the mechanism of fault–stress field interactions and for understanding the dynamic evolution mechanism of the uplift of the Qinghai–Tibet Plateau.

Adaptive estimation of the Gutenberg–Richter b value using a state space model and particle filtering

Earthquakes follow an exponential distribution referred to as the Gutenberg–Richter law, which is characterized by the b value that represents a ratio of the number of large earthquakes to that of small earthquakes. Spatial and temporal variation in the b value is important for assessing the probability of a larger earthquake. Conventionally, the b value is obtained by a maximum-likelihood estimation based on past earthquakes with a certain sample size. To properly assess the occurrence of earthquakes and understand their dynamics, determining this parameter with a statistically optimal method is important. Here, we discuss a method that uses a state space model and a particle filter, as a framework for time-series data, to estimate temporal variation in the b value. We then compared our output with that of a conventional method using data of earthquakes that occurred in Tohoku and Kumamoto regions in Japan. Our results indicate that the proposed method has the advantage of estimating temporal variation of the b value and forecasting magnitude. Moreover, our research suggests no heightened probability of a large earthquake in the Tohoku region, in contrast to previous studies. Simultaneously, there is the potential of a large earthquake in the Kumamoto region, emphasizing the need for enhanced monitoring.

Deep fault sliding rates for Ka-Ping block of Xinjiang based on repeating earthquakes

Abstract The seismically active Ka-Ping Block within Xinjiang, China, represents a zone of potential earthquake hazards, and existing surface measurements cannot fully reflect the area’s sub-surface slip rates. To determine these slip rates and characterize the level of hazard that the study area may face in future years, using a cross-correlation of waveforms, we identified 432 repeat sequences along large faults (F1–F5) in the Ka-Ping Block between September 2009 and April 2022 and computed the annual slip rate for every sequence with the empirical relationship of the moment and the seismic magnitude. Spatial distribution images and temporal evolution characteristics of deep deformation in fault zones were constructed. We obtained five asperities in the Ka-Ping Block, the western portion of the PiQiang fault (F4) had a larger yearly slide rate than its eastern portion, and the southwest and eastern areas of the KEP station show an elevated risk of seismic activity within the next two years.

Inverting Geodetic Strain Rates for Slip Deficit Rate in Complex Deforming Zones: An Application to the New Zealand Plate Boundary

AbstractThe potential for future earthquakes on faults is often inferred from inversions of geodetically derived surface velocities for locking on faults using kinematic models such as block models. This can be challenging in complex deforming zones with many closely spaced faults or where deformation is not readily described with block motions. Furthermore, surface strain rates are more directly related to coupling on faults than surface velocities. We present a methodology for estimating slip deficit rate directly from strain rate and apply it to New Zealand for the purpose of incorporating geodetic data in the 2022 revision of the New Zealand National Seismic Hazard Model. The strain rate inversions imply slightly higher slip deficit rates than the preferred geologic slip rates on sections of the major strike‐slip systems including the Alpine Fault, the Marlborough Fault System and the northern part of the North Island Fault System. Slip deficit rates are significantly lower than even the lowest geologic estimates on some strike‐slip faults in the southern North Island Fault System near Wellington. Over the entire plate boundary, geodetic slip deficit rates are systematically higher than geologic slip rates for faults slipping less than one mm/yr but lower on average for faults with slip rates between about 5 and 25 mm/yr. We show that 70%–80% of the total strain rate field can be attributed to elastic strain due to fault coupling. The remaining 20%–30% shows systematic spatial patterns of strain rate style that is often consistent with local geologic style of faulting.

Study of tsunami source as preparation for tsunami modeling in Sulawesi

The Sulawesi region is prone to earthquakes due to the existence of a Subduction Zone which can generate a tsunami so that tsunami modeling is important as a tsunami mitigation effort in the future. The purpose of this research is to study the maximum earthquake potential in the Sulawesi Subduction Zone and to model the tsunami source with a multi-deformation scheme. The research method is a literature study using the 2017 National Earthquake Center book, tsunami modeling using an earthquake scenario with a magnitude of 8.5 Mw, a depth 20 Km, fault dimension modeling using global mapper software based on the Scaling law, fault dimensions with a length of the fault area and a width of the fault area, the earthquake parameters in the study consist of magnitude, epicentre depth, dip, slip, fault area length, the width of the fracture area and the dislocations. Tsunami source modeling uses the multi-fault. The results of this study are the maximum potential for an earthquake of around 8.5 Mw, the shape of the earthquake deformation and parameters as well as the tsunami source model that describes the sea level conditions experiencing an increase of 5,7 meters and for the decrease in sea level reaching -5.9 meters.

Seismic Resilience of Emergency Departments: A Case Study

In this work, the seismic resilience of the Emergency Department of a hospital complex located in Tuscany (Italy), including its nonstructural components and organizational features, has been quantified. Special attention has been paid to the ceilings, whose potential damage stood out in past earthquakes. A comprehensive metamodel has been set, which can relate all the considered parameters to the assumed response quantity, i.e., the waiting time of the yellow-code patients arriving at the Emergency Department in the hours immediately after the seismic event. The seismic resilience of the Emergency Department has been measured for potential earthquakes compatible with the seismic hazard of the area.

Overpressure Estimation Based on Velocity Data Analysis in The Subduction Zone of Hyuga-nada at Western Nankai Trough, Japan

Subduction zone is one of the areas which has great potential of earthquake. Nankai trough in Japan is such an area with subduction zone where earthquake records are well archived, despite its complexity. Also, slow earthquakes have been detected in this zone over the past 20 years, so that there are many opportunities to understand the dynamics and deformation in such an active setting. To expand the knowledge about slow earthquake which might occur and trigger a bigger earthquake, this study wants to infer the relationship between overpressure, one of the states and properties of seismogenic zone, and tremors. To carry out this research, 4 velocity models of seismicity line taken in Hyuga-nada are used. And the recorded tremor data placed around the lines came from Yamashita. In correlating the overpressure and tremors, this research is started by converting the Vp model to porosity model using Wyllie equation to predict the pore pressure conditions in the area. Then, the model will be used for fitting the actual data. Assuming there is an exact location following the normal compaction curve as a function of effective stress, it can be used for estimating the overpressure. Overpressure is economized by comparing the observed porosity and the reference curve at the same depth below seafloor. Potential overpressure occurred may be associated with areas of low Vp. The estimated overpressure is in the range of 1.2 to 12 MPa in the depth range of 700 to 4000mbsf. This study also concludes that the overpressure zone overlaps with the tremor location, although the overpressure value estimated is also still uncertain due to the uncertainty of the density value used.

Large‐scale seismic soil–structure interaction analysis via efficient finite element modeling and multi‐GPU parallel explicit algorithm

AbstractAs urban population increases, integrated underground–aboveground complexes are being constructed at growing paces in major cities. The seismic analysis of such complexes is crucial for the safety and functionality in the threat of potential earthquake disasters. However, fine‐grained numerical modeling and analysis of such large and complex structures are still inefficient due to the consideration of the soil–structure interaction (SSI). To address this challenge, an efficient approach for numerical modeling of large‐scale seismic SSI analysis is presented in this paper to overcome the limitations of existing finite element analysis (FEA) software. Moreover, a multi‐graphic processing unit (GPU) parallel explicit algorithm is implemented for the nonlinear dynamic SSI problems to further increase the computational efficiency. A large underground–aboveground complex project in China is used as an example to demonstrate the capability of the integrated method. The accuracy and reliability of the multi‐GPU parallel explicit finite element algorithm for SSI analysis (GFEA‐SSIA) are verified through a comparative analysis of the linear‐elastic and nonlinear dynamic response of the building calculated by GFEA‐SSIA and common FEA software. Finally, the structural response and structural damage of the underground–aboveground complex are analyzed under multidirectional seismic motions, and the damage distributions of the structures are provided.