Earth Tremors Research Articles

Forensic investigation of Gumbasa irrigation main canal damage due to large-scale flow liquefaction in Sibalaya caused by the 2018 Sulawesi Earthquake

This study conducted an extensive soil investigation in the Sibalaya liquefaction area to identify the Gumbasa main canal’s damage triggered by flow liquefaction. Several field tests and trenches with approximately 4 m were excavated to observe liquefied soil layers directly near the canal. A borehole, standard penetration test, and multichannel analysis surface waves (MASW) were performed beside the trench to obtain each layer’s penetration resistance. This research aims to understand the landslide’s whole aspect. The ground movements were analyzed by using satellite photos before and after the earthquake. The displacement of the main canal, the typical damage inventory, and the proposed reconstruction of the main canal are the focus of this study. As a result of the forensic investigation, the liquefied layers and debris flow contributing to the massive landslide were identified to impact the primary canal. The typical damage of the canal was due to surface rupture that occurred both horizontally and vertically. A solution for reconstructing the main canal is to use a flexible pipe canal structure. That will be resilient to future earthquake and ground movements, stabilize the ground downslope of the existing canal to limit the risk of future lateral movement in future earth tremors.

Legless soft robots capable of rapid, continuous, and steered jumping

Jumping is an important locomotion function to extend navigation range, overcome obstacles, and adapt to unstructured environments. In that sense, continuous jumping and direction adjustability can be essential properties for terrestrial robots with multimodal locomotion. However, only few soft jumping robots can achieve rapid continuous jumping and controlled turning locomotion for obstacle crossing. Here, we present an electrohydrostatically driven tethered legless soft jumping robot capable of rapid, continuous, and steered jumping based on a soft electrohydrostatic bending actuator. This 1.1 g and 6.5 cm tethered soft jumping robot is able to achieve a jumping height of 7.68 body heights and a continuous forward jumping speed of 6.01 body lengths per second. Combining two actuator units, it can achieve rapid turning with a speed of 138.4° per second. The robots are also demonstrated to be capable of skipping across a multitude of obstacles. This work provides a foundation for the application of electrohydrostatic actuation in soft robots for agile and fast multimodal locomotion.

Menelisik Ayat-Ayat Gempa Pada Hari Kiamat (Analisis Tafsīr Al-Jawāhir Fi Tafsīr Al-Qurān Al-Karim karya Tantawi Jauhari)

The discourse of this research relates to the earthquake verses on the Day of Judgment, by looking at the interpretation of Tantawi Jauhari on the interpretation of Qs. Al-Hajj verse 1 and Qs. Al-Zalzalah verse 1 on the word Zalzalah (earthquake), Qs. Al-Waqiah verse 4 on the word Rajj (great shaking), Qs. Al-Hāqah verse 14 on the words Dakk (the earth collides, the earth shakes), Qs. Al-Nazi'at verse 6 on the word Rajfah (great earthquake), with his interpretation, tries to contextualize the text with the current conditions by using a scientific interpretation approach. So that it raises positive implications that are axiological or applicable that the verses of the Qur'an have continuity in providing instructions for humans which are packaged in a relevant language. And also negative implications, which lead to misunderstandings regarding the verses of mubham, muhkam, and mutasyabihat; it is as if the Qur'an came down in relation to events that are happening, even though not all of the verses are like that; and the religious values of the Koran are reduced.

Review: Eros Ideologies: Writings on Art, Spirituality, and the Decolonial, by Laura E. Pérez

Review: <i>Eros Ideologies: Writings on Art, Spirituality, and the Decolonial</i>, by Laura E. Pérez

Constraining Jumps in Density and Elastic Properties at the 660 km Discontinuity Using Normal Mode Data via the Backus‐Gilbert Method

AbstractWe apply the Backus‐Gilbert approach to normal mode center frequency data, to constrain jumps in P, S, bulk‐sound speed and density at the “660” discontinuity in the earth’s mantle (∼650–670 km depth). Different 1‐D models are considered to compute sensitivity kernels. When using model PREM (Dziewonski &amp; Anderson, 1981, Physics of the Earth and Planetary Interiors, 25, 297–356. doi:10.1016/0031‐9201(81)90046‐7) as reference, with a “660” at 670 km depth, the best‐fitting jumps in density, P‐ and S‐wave speeds range from (5.1–8.2)%, (5.3–8.0)%, (5.0–7.0)%, respectively, so the PREM values lie outside the ranges of acceptable density and P wave speed jumps. When shifting the depth of “660” to 660 km, the density and S wave speed jumps increase, while the P‐wave speed jump decreases. Normal mode data do not support a global transition at 650 km depth. The density jumps are closer to those of pyrolite than PREM, while our bulk‐sound wave speed jumps suggest a larger garnet proportion at “660.”

Densification of Controls and Gravity Stations for Monitoring of Earth Tremor and other Natural Disasters in Nigeria. A case study of Ijebu-Ode

Densification of Controls and Gravity Stations for Monitoring of Earth Tremor and other Natural Disasters in Nigeria. A case study of Ijebu-Ode

Observation of the long-period monotonic seismic waves of the November 11, 2018, Mayotte event by Iranian broadband seismic stations

On November 11, 2018, an event generating long-lasting, monotonic long-period surface waves was observed by seismographs around the world. This event occurred at around 09:28 UTC east of the Mayotte Island, in the Indian Ocean off the coast of East Africa. This event is unusual due to the absence of body waves in the seismograms and no feeling of earth shaking by people locally. The purpose of this study is to investigate this unusual event using the waveforms recorded by 26 stations of the Iranian National Broadband Seismic Network. The stations are located at epicentral distances ranging from 4542 to 5772 km north-northeast of the event’s epicenter. The arrival of monochromatic long-period signals is visible around 10 UTC in the recordings of all the stations and the signals lasted for more than 30 min. Frequency analysis of the seismograms shows a clear peak at 0.064 Hz (15.6 s/cycle). The maximum amplitude of the transverse components is less than a half of the radial components. This is in agreement with the theoretical radiation pattern of Rayleigh and Love waves at a frequency of 0.06 Hz for a vertical compensated linear vector dipole source mechanism. The average apparent phase velocities were calculated as 3.31 and 2.97 km/s, in the transverse and radial directions, corresponding, respectively, to Love and Rayleigh waves in the frequency range of 0.05–0.07 Hz. A surface wave magnitude of Ms 5.07 ± 0.22 was estimated. Just before the monochromatic signal arrives, there is some dispersion in the surface waves. This observation may suggest a regular earthquake of Ms 4.3 ± 0.11 that triggered the November 11, 2018, event. The difference between the arrival times of the recorded surface waves of the two events is estimated to be less than 31 s, and most likely of ~ 7 s only.

Research on the Teaching Reform of "Double Tutor System" in Art Design Major

With the continuous progress and development of modern society, earth shaking changes have taken place in all fields of people’s life, which not only has higher requirements for the quality of higher education, but also has improved the cultural pursuit in the field of art. Therefore, in order to more effectively improve the quality of art talents training in the new era, colleges and universities should combine the development trend of modern society in real time, take employment as the guidance to develop a more perfect curriculum teaching system, and take more scientific technical means, in order to further expand the ways to improve the quality of talent training, constantly strengthen the comprehensive quality of art talents, and enhance the core competitiveness of art design talents in essence.

Velocity planning in multi-axis EDM based on a coder-player architecture

With a higher requirement on machining accuracy in electrical discharging machining (EDM), there is a drastically increased number of multi-axis line segments for machining complex workpieces. High speed jumping is needed for a conducive discharge gap status. The increased number of line segments, however, makes the implementation of high-speed jumping difficult. To alleviate the online computational burden for velocity planning, this paper proposes a multi-axis velocity planning based on a coder-player architecture. Under this architecture, a multi-axis feeding trajectory is represented by a series of double non-uniform rational B-spline (NURBS) curves, which are then interpolated by the unit arc length increment interpolation (UALII) method. Based on the interpolation points with a resolution of a basic length unit (BLU), a velocity limit curve is generated by considering simultaneously the constraints on chord error, acceleration and jerk. The velocity planning is implemented under a coder-player architecture. As a trajectory represented by a double-NURBS curve has C2 continuity, velocity losses can be avoided at junctions between line segments, thus smoothing of line segments at junctions is unnecessary in jumping. Machining tests showed that by the use of the velocity planning based on double-NURBS curves, the machining time for one channel of a shrouded blisk can be decreased by 29.38%.

On using the modularity of recurrence network communities to detect change-point behaviour

The behaviour of a dynamical system can be examined from time series using the technique of recurrence plots through visualization and quantification methods. One such method is the quadrant scan in which a recurrence plot of a time series is converted into a second time series whose local maxima can be identified and interpreted as possible transitions in dynamic behaviour. A recurrence plot can also be represented as a complex network. A quadrant scan can similarly be thought of as a partition of the network vertices into two communities. Here, we argue that different dynamic behavioural regimes can be realized as network communities and the quality of such partitions can be assessed using modularity. Thereby, community modularity can be used as an alternative to the quadrant scan. We investigate this correspondence with respect to two promising arenas for quadrant scan uptake, namely, concept drift detection from machine learning and tipping point or failure and damage monitoring in system maintenance. We also examine two additional data sets to highlight the potential of the methods. These are a geophysical time series of earth tremor data and a physiological time series of an electrocardiogram.

Effects of atrazine short-term exposure on jumping ability and intestinal microbiota diversity in male Pelophylax nigromaculatus adults.

Atrazine, a common chemical pesticide, has toxicity to adult and juvenile amphibians in natural ecosystems; however, it is more common to study its effects on larvae instead of adults. This study assessed the impacts of atrazine in water through short-term exposure (7 days) on male black spotted frog (Pelophylax nigromaculatus) adults fed every day. The jumping ability, including jumping height, distance, time, and speed, was measured by 3D motion analysis software, and the intestinal content microbiota was determined by 16S rRNA amplicon sequencing with QIIME software. The results showed that male P. nigromaculatus exposure to 200 and 500 μg/L atrazine significantly increased jumping distance and jumping time compared to control groups. Conversely, 500 μg/L atrazine treatments significantly decreased the diversity and changed the composition and structure of intestinal content microflora in male P. nigromaculatus compared to control groups. At the phylum level, Chlamydiae was only detected in the control group, and Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria were the dominant microflora in the atrazine treatment groups. At the genus level, the abundance of Lactobacillus and Weissella significantly increased in atrazine treatment groups compared to control groups. This study can provide a new framework based on movement behavior and intestinal microbiota to evaluate the response of amphibians to short-term exposure to environmental pollution.

Effect of Lead Exposure on Jumping Ability in Pelophylax nigromaculata.

Jumping ability determines the likelihood of survival and reproduction of amphibians. To study the toxic effect of lead (Pb) on the jumping ability of amphibians, Pelophylax nigromaculata were treated with 0, 1 and 10 mg/L Pb for 10 days and 20 days each. The results showed that for both treatment time (10 days and 20 days), compared to the control group, the 1 mg/L Pb treatment had no significant effect on jumping parameters. Compared to the control group, the maximum jumping height, distance, speed and acceleration in the 10-day 10 mg/L Pb treatment group increased significantly, but after 20 days the jumping parameters decreased significantly. With an increase in duration and concentration, the correlation coefficient and the correlation between these jumping parameters decreased. Our results indicate that an exposure to 10 mg/L Pb for 20 days has a significant negative effect on the jumping ability of amphibians.

Digital Financial Transaction Security Based on Blockchain Technology

Blockchain technology is currently recognized as the most potential new key technology, it can bring earth shaking changes, it is expected to trigger a new round of technological innovation and industrial change, and cause market attention. The purpose of this paper is to study the security of digital financial transactions based on blockchain technology. Firstly, the security of sdte is analyzed, and the DoS attacks that each role may launch, the attacks that a single role may send, and the attacks that can be launched by multiple roles in collusion are analyzed. It shows that sdte can resist these attacks and has strong security. Then, the related environment of the system test is described. Then, the performance test and analysis are carried out from the key security transmission, the execution of smart contract in the trusted environment SGX and the total running time. The experimental results show that the extra time consumed by using the k-nearest neighbor (KNN) algorithm to process data is less than 0.45s, At the same time, the additional cost brought by the system is also acceptable.

English

Vertical and horizontal motion of the solid earth surface due to geological and geodynamical phenomena are generally consequences of terrain deformation. Variations as a result of the deformation affect structures, particularly large storage facilities that are steel and/or concrete in nature. The criticality of these phenomena underscores the need to carryout regular measurements and monitoring of its effect in all dimension. Over the years, methods and instrumentation for subsidence monitoring has evolved from the conventional to the recently high definition surveying approach with an increasing need to detect and analyse deformation changes with clarity at any given time. The aim of this work was to appraise the high definition surveying approaches in subsidence dynamics of crude oil storage facilities. Classical instrumentations and the terrestrial laser scanning equipment were deployed based on the principles of geodetic positioning and mapping for overlity, verticality and radial displacement parameters determination using the two approaches. This paper will provide spatial information in terms of point clouds, 2D and 3D models, vertical and radial displacement of the crude oil storage facility. The work will further demonstrate the optimal capability of high definition surveying approach in our quest to constantly manage the complexities associated with subsidence. Several crude oil storage facilities in addition to other private storage facilities all over the country, require a policy to ensure regular monitoring and analysis of these facilities especially with the trend of earth tremors being experienced in parts of the country. &nbsp; Key words: Subsidence, high definition surveying, radial displacement, crude oil facility, geodetic positioning.

In-air fast response and high speed jumping and rolling of a light-driven hydrogel actuator

Stimuli-responsive hydrogel actuators have promising applications in various fields. However, the typical hydrogel actuation relies on the swelling and de-swelling process caused by osmotic-pressure changes, which is slow and normally requires the presence of water environment. Herein, we report a light-powered in-air hydrogel actuator with remarkable performances, including ultrafast motion speed (up to 1.6 m/s), rapid response (as fast as 800 ms) and high jumping height (~15 cm). The hydrogel is operated based on a fundamentally different mechanism that harnesses the synergetic interactions between the binary constituent parts, i.e. the elasticity of the poly(sodium acrylate) hydrogel, and the bubble caused by the photothermal effect of the embedded magnetic iron oxide nanoparticles. The current hydrogel actuator exhibits controlled motion velocity and direction, making it promising for a wide range of mobile robotics, soft robotics, sensors, controlled drug delivery and other miniature device applications.

A review of natural geological hazards in Oman

Oman has a diverse geology and physiography as a result of its location close to active tectonic plates. Oceanic and continental rocks spanning in age from the Proterozoic to the Tertiary are overlain by mobile sediments of the Quaternary. Infrastructure is expanding due to demands for industrial and residential land and associated transport networks, though the geology can abate this progress. Shifting dunes threaten road networks, residential areas and agricultural land. Ophiolite and mantle rocks can contain natural asbestos minerals which when fragmented can be hazardous to health. Large expanses of carbonate and evaporitic rocks are prone to karst morphology and where existing examples include caves and sinkholes. The recent tectonic events have given rise to earth tremors, fissures, ground displacements and tsunamis. A review of the main natural hazards in Oman is presented to assist with high-level land development planning in accordance with the geology and minimise its potentially hazardous effects.

Aeromagnetic mapping of fault architecture along Lagos–Ore axis, southwestern Nigeria

AbstractA seismic wave is released when there is sudden displacement on a fault plane. The passage of this wave along the fault plane or within the lithosphere could result in ground shaking or vibration at the surface of the Earth. To provide a geophysical explanation to this phenomenon, the high-resolution aeromagnetic data of the sedimentary terrain and part of the Basement Complex of Southwestern Nigeria were processed and interpreted to provide fault architecture of the area, which could serve as conduit for the passage of seismic energy in the study area. High-resolution aeromagnetic data along the Lagos–Ore axis are processed for fault mapping in the study area. The reduced-to-equator (RTE) residual aeromagnetic data used were enhanced using the total horizontal derivative (THD) and upward continuation (UC) filtering techniques on Oasis Montaj 6.4.2 (HJ) software. The resultant maps were overlaid and compared with the plotted RTE residual maps for relevant interpretations. Varying signatures of magnetic anomalies are grouped into high (57.9–89.1 nT), intermediate (38.2–57.9 nT), and low (4.0–38.2 nT) magnetic intensities, which are associated with contracting basement rocks features. The obtained lineaments from the THD reveal areas of various deformations such as brittle, which is associated with faults/fractures, and ductile deformation, which is associated with folds of geological features. The faults, as depict by the UC map, reveal different depth ranges of 500–2250 m at the western side and 1,500–1,250 m at the northwestern area of the study. Since it has been on record that September 11, 2009, earth tremor of magnitude 4.4, with the epicenter at Allada, Bennin Republic, 128 km west of Lagos, Nigeria occurred within the study area, it can be inferred that the established geologic fault architecture could be responsible for the hazard and be part or synthetic to the Ifewara-Zungeru fault in Nigeria.

The Unshakable Kingdom through the Shaking of Heaven and Earth in Heb 12:26–29

Abstract In Heb 12:26–29, the author envisages the unshakable kingdom that will be established through the shaking of heaven and earth. The image of the cosmic shaking caused many interpreters to understand the present passage as the vision of the immaterial, ideal world, which will come after the destruction of the creation, reflecting the background of the Platonic dualism. Nevertheless, the usages of the main terms, χρηµατίζω and µετάθεσις, and the OT citations in the present passage suggest that this understanding is not indisputable. In this article, it is argued that some Jewish apocalyptic texts provide an alternative background of the text, offering a vision of the eschatological kingdom established by the revealed heavenly realm and the renewed creation.

UK meteotsunamis: a revision and update on events and their frequency

<scp>UK</scp> meteotsunamis: a revision and update on events and their frequency

Preliminary Investigation of Seismicity in Parts of North Central Nigeria, Using High Resolution Aeromagnetic Data

Qualitative analysis of Aeromagnetic data of parts of north central Nigeria had been carried out with the aim to delineate seismic prone areas. The study area is bounded with latitude 9. 00o to 10. 00oN and longitude 7.00o to 9.00oE with an estimated total area of 24,200 km2. Vertical derivatives and upward continuation filters were used to enhances long wavelength anomalies which could give preliminary information about the magnetic structures present in the study area. The total magnetic intensity map shows both positive and negative anomalies with susceptibility ranging from 33487.7 nT to 33800.9 nT. The high magnetic susceptibilities dominated in the basement region around the north-eastern and north-western parts of the study area which corresponds to Naraguta, Jemma and Kafanchan area. Based on the geology of the area this is attributed to granite, schist and migmatite rocks. The low magnetic values are made of sediment deposition also dominates the south-western part of the study area, corresponding to Abuja and Gitata. The area with magnetic susceptibility values ranging between 33506.6 nT and 33653.8 nT indicates alluvium deposite around Bishini and Kachia area. Lineament from First Vertical Derivative trend in the northeast-southwest and east-west directions, which is an extension from Romanche Fracture Zone. Majority of this lineament trends in the same directions as the Romanche Fault Line which continues at 25 km and 30 km into n inferred closure within the study area which is trending along north-west direction. This, closure occurs probably because of the existence of the paleo fracture zone (Romanche Fracture Zone) within the study area. At 40 km and at 80 km a regional trend in the NE-SW direction in (porphyritic) basement rocks. At the northeast and southeastern part of the area which is made up of basement complex that corresponds to areas around Gitata, Kafanchaan and Jemma are prone to tectonic activities while the southwestern part of the area around Abuja is seismic free. It is suggested that those lineaments identified, most especially at the southeastern part could be the reason for the shaking of the subsurface which result into earth tremors.