scholarly journals Earthquake monitoring of the Baribis Fault near Jakarta, Indonesia, using borehole seismometers

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ruben Damanik ◽  
Pepen Supendi ◽  
Sri Widiyantoro ◽  
Nicholas Rawlinson ◽  
A. Ardianto ◽  
...  
Keyword(s):  
Active Faults ◽  
Primary Objective ◽  
Low Noise ◽  
Fault Line ◽  
Focal Mechanism Solutions ◽  
Noise Characteristics ◽  
Nearest Point ◽  
Seismic Experiment ◽  
Borehole Seismic ◽  
Good Agreement

AbstractThe geological setting of Jakarta and its immediate surroundings are poorly understood, yet it is one of the few places in Indonesia that is impacted by earthquakes from both the Java subduction zone and active faults on land. In this study, a borehole seismic experiment with low noise characteristics was deployed to record seismic activity on the ~ E-W oriented Baribis Fault, which is ~ 130 km long, passes to the south of Jakarta, and is only ~ 20 km away at its nearest point. A primary objective of this study is to determine whether this fault is seismically active, and therefore, whether it might pose a threat to nearby population centers, including Jakarta in particular. A total of seven broadband instruments that spanned Jakarta and the surrounding region were installed between the end of July 2019 and August 2020, during which time we were able to detect and locate 91 earthquakes. Two earthquakes were located close to the Baribis Fault line, one of which was felt in Bekasi (southeast of Jakarta) where it registered II-III on the Modified Mercalli Intensity (MMI) scale. The focal mechanism solutions of these events indicate the presence of a thrust fault, which is in good agreement with previous studies, and suggest that the Baribis Fault is active.

scholarly journals Use of Borehole Seismometers in Earthquake Monitoring at the Baribis Fault Leading to Jakarta, Western Java

2020 ◽  
Author(s):  
Ruben Damanik ◽  
Sri Widiyantoro ◽  
Pepen Supendi ◽  
Yayan M. Husni ◽  
Z. Zulfakriza ◽  
...  
Keyword(s):  
Active Faults ◽  
Focal Mechanism Solution ◽  
Location Determination ◽  
Fault Type ◽  
Australian Plate ◽  
Seismic Experiment ◽  
Surrounding Areas ◽  
Borehole Seismic ◽  
Plate Subduction

Abstract The region of Jakarta and its vicinity is one of the least understood geological domains in Java Island, Indonesia. Yet, the region is one of the few places which are often impacted by earthquakes from the Indo-Australian Plate subduction zone as well as on land active faults. In this study, a borehole seismic experiment was designed to unravel the seismic activity of the Baribis Fault, which continues and leads to Jakarta. This passive source experiment was composed of seven broadband instruments that extended across the Jakarta region and surrounding areas. The experiment recorded seismic data from the end of July 2019 to August 2020. We located 91 events of hypocenter location determination of the data recording; one event was located closely to the Baribis Fault line that continues to Jakarta and was felt in Bekasi (Southeast of Jakarta) at up to II-III on the Modified Mercalli Intensity (MMI) scale. The focal mechanism solution of this event shows an oblique thrust fault type. This event is evidence that the Baribis Fault is active.

scholarly journals A Four-Channel Low-Noise Readout IC for Air Flow Measurement Using Hot Wire Anemometer in 0.18 μm CMOS Technology

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4694
Author(s):  
Kyeongsik Nam ◽  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Gyuri Choi ◽  
Taeyup Kim ◽  
...  
Keyword(s):  
Supply Voltage ◽  
Air Flow ◽  
Low Noise ◽  
Cmos Process ◽  
Significant Information ◽  
Flow Measurements ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Op Amp ◽  
Noise Characteristics

Air flow measurements provide significant information required for understanding the characteristics of insect movement. This study proposes a four-channel low-noise readout integrated circuit (IC) in order to measure air flow (air velocity), which can be beneficial to insect biomimetic robot systems that have been studied recently. Instrumentation amplifiers (IAs) with low-noise characteristics in readout ICs are essential because the air flow of an insect’s movement, which is electrically converted using a microelectromechanical systems (MEMS) sensor, generally produces a small signal. The fundamental architecture employed in the readout IC is a three op amp IA, and it accomplishes low-noise characteristics by chopping. Moreover, the readout IC has a four-channel input structure and implements an automatic offset calibration loop (AOCL) for input offset correction. The AOCL based on the binary search logic adjusts the output offset by controlling the input voltage bias generated by the R-2R digital-to-analog converter (DAC). The electrically converted air flow signal is amplified using a three op amp IA, which is passed through a low-pass filter (LPF) for ripple rejection that is generated by chopping, and converted to a digital code by a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC). Furthermore, the readout IC contains a low-dropout (LDO) regulator that enables the supply voltage to drive digital circuits, and a serial peripheral interface (SPI) for digital communication. The readout IC is designed with a 0.18 μm CMOS process and the current consumption is 1.886 mA at 3.3 V supply voltage. The IC has an active area of 6.78 mm2 and input-referred noise (IRN) characteristics of 95.4 nV/√Hz at 1 Hz.

The multi-functional rotor aerodynamic and aeroacoustic test platform at HKUST

2021 ◽  
Vol 263 (2) ◽  
pp. 4410-4417
Author(s):  
Han Wu ◽  
Chuntai Zheng ◽  
Peng Zhou ◽  
Ryu Fattah ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Phase Locking ◽  
Axial Flow ◽  
Low Noise ◽  
Test Rig ◽  
Tunnel Wall ◽  
Noise Characteristics ◽  
Piv Measurement ◽  
Test Platform ◽  
Semi Empirical

This paper describes the multi-functional rotor noise and aerodynamics test platform at the Hong Kong University of Science and Technology (HKUST). To investigate the noise characteristics of propellers with aerodynamic flows, the test rig is installed in the 2.5×2 (m) low-speed and low-noise wind tunnel in the Aerodynamic and Acoustic Facility (AAF) at HKUST. The wind tunnel can facilitate flow from 0 to 40 m/s. The test rig is assembled in a turntable on the ceiling of the tunnel wall, which enables the testing range of pitch angle can vary from 0° (axial flow) to 90° (parallel flow), with an accuracy of 0.1°. The noise produced by the rotor is measured by a set of wall-mounted surface microphones. Semi-empirical calibration is conducted to quantify the noise reflection by the tunnel walls. A low-noise struct has been designed and manufactured to locate a set of far-field microphones equipped with nosecone, to improve the quality of acoustic measurement inside the flow. In addition, a synchronized system is developed to conduct the phase-locking Particle Image Velocimetry (PIV) measurement on the rotor, to study the flow pattern to better understand the noise generation mechanism.

scholarly journals Moment magnitude estimates for Central Anatolian earthquakes using coda waves

2019 ◽  
Author(s):  
Tuna Eken
Keyword(s):  
Empirical Relation ◽  
Active Regions ◽  
Moment Magnitude ◽  
Central Anatolia ◽  
Coda Wave ◽  
Seismic Experiment ◽  
Tectonically Active ◽  
Passive Seismic ◽  
Passive Seismic Experiment ◽  
Good Agreement

Abstract. Proper estimate of moment magnitude that is a physical measure of the energy released at earthquake source is essential for better seismic hazard assessments in tectonically active regions. Here a coda wave modeling approach that enables the source displacement spectrum modeling of examined event was used to estimate moment magnitude of central Anatolia earthquakes. To achieve this aim, three component waveforms of local earthquakes with magnitudes 2.0 ≤ ML ≤ 5.2 recorded at 72 seismic stations which have been operated between 2013 and 2015 within the framework of the CD-CAT passive seismic experiment. An inversion on the coda wave traces of each selected single event in our database was performed in five different frequency bands between 0.75 and 12 Hz. Our resultant moment magnitudes (MW-coda) exhibit a good agreement with routinely reported local magnitude (ML) estimates for study area. Finally, we present an empirical relation between MW-coda and ML for central Anatolian earthquakes.

scholarly journals Wide-field Astronomy with Tech Pan Film - A Positive Outlook for Schmidt Photography

1995 ◽  
Vol 148 ◽  
pp. 96-103 ◽  
Author(s):  
Quentin A Parker ◽  
Steven Phillipps ◽  
David Morgan
Keyword(s):  
Economic Benefits ◽  
Low Noise ◽  
Area Coverage ◽  
Wide Field ◽  
Medium Term ◽  
Significant Information ◽  
Field Surveys ◽  
Noise Characteristics ◽  
Co Addition ◽  
Positive Outlook

AbstractThe introduction of film-based Kodak Technical Pan emulsion at the UKST has led to a new lease of life for deep, wide-field astrophotography. This is because the excellent imaging, resolution and low noise characteristics of Tech Pan typically yield a one magnitude depth gain over equivalent IIIa-F plates. Many new projects are underway to take advantage of the significant information gains. The cheap cost of film and ease of transportation gives direct economic benefits too. Tech Pan could also offer a medium term, competitive alternative to CCD mosaics for providing new, deep, wide-field surveys via stacking of several digitised exposures of the same field. A one magnitude gain could result from the stacking of just 6 Tech Pan films to yield an R ∼ 23.5–24. Even without digital co-addition the largest current CCDs cannot hope to match Tech Pan’s inherent ∼ 3 µm resolution and the 40 square degree area coverage of the UKST.

Evaluation of Noise Characteristics of Drainage and Water Supply Systems in Apartment Bathrooms

2014 ◽  
Vol 1025-1026 ◽  
pp. 987-990
Author(s):  
Jun Oh Yeon ◽  
Kyoung Woo Kim ◽  
Kwan Seop Yang ◽  
Byung Kwon Lee
Keyword(s):  
Water Supply ◽  
Noise Level ◽  
Drainage System ◽  
Low Noise ◽  
Sound Level ◽  
Water Supply Systems ◽  
Apartment Building ◽  
Noise Characteristics ◽  
Measurement Results ◽  
Supply Systems

We have developed a low-noise drainage system, which was installed in bathrooms of apartment building units as well as in a mock-up test building, to evaluate the noise level in order to reduce the noise produced in the bathrooms of multiunit dwellings. The drainage system installed in the mock-up building consists of six types of detachable drains, and the level of noise produced during toilet use in the upper unit was measured in the lower unit. The measurement results showed that low-noise drainage 4 exhibited the Leq(equivalent continuous sound level) at 34.7 dB(A). The noise measurement results of various types of low-noise drains installed in an apartment building showed that the Leqduring toilet use was 46.7 dB(A) on average, and the Leqduring sink use was 40.5 dB(A) on average.

Indication of active Faults in the New Madrid Seismic Zone from Precise Location of Hypocenters

1988 ◽  
Vol 59 (4) ◽  
pp. 123-131 ◽  
Author(s):  
L. Himes ◽  
W. Stauder ◽  
R. B. Herrmann
Keyword(s):  
Active Faults ◽  
P Wave ◽  
New Madrid Seismic Zone ◽  
Supporting Evidence ◽  
Seismic Zone ◽  
Low Velocity ◽  
Focal Mechanism Solutions ◽  
Velocity Models ◽  
Planar Surfaces ◽  
New Madrid

Abstract The hypocenter locations of the larger and better recorded earthquakes of the New Madrid seismic zone are examined in order to determine how closely the hypocenters lie along planar surfaces, thus relating the foci to active fault surfaces. For this purpose more than 500 earthquakes of the region have been selected for study, based on the number (7 or more) of observing stations used in the initial hypocenter location and on the quality of the P-wave onset. These events are relocated using a joint hypocenter-velocity-depth (JHVD) algorithm. The relocated earthquakes are separated geographically into three trends: ARK, the southwest trending zone from Caruthersville, Missouri, to Marked Tree, Arkansas; DWM, the northeast trending zone from New Madrid to Charleston, Missouri; and CEN, the central, left-stepping offset zone from Ridgely, Tennessee, to New Madrid, Missouri. Vertical profiles taken along and across the ARK and DWM trends verify the strike and dip of dominantly strike slip motion on near vertical active faults along these trends. These results agree with previously determined composite focal mechanism solutions for these trends. No coherent picture has been obtained for the CEN trend. As a by-product of the study, velocity models from the JHVD inversion are found to be reasonably uniform throughout the New Madrid seismic zone, and to offer supporting evidence for the presence of a shallow low velocity zone in the central portion of the Mississippi embayment.

Measurement and Analysis of Noise Characteristics for Diesel Engine

2005 ◽  
Author(s):  
Guangpu Liu ◽  
Hongxia Pan ◽  
Jinying Huang
Keyword(s):  
Spectral Analysis ◽  
Diesel Engine ◽  
Noise Source ◽  
Low Noise ◽  
Coherence Analysis ◽  
Vehicle Interior ◽  
Noise Characteristics ◽  
Measurement And Analysis ◽  
Analysis System ◽  
Low Noise Design

The vehicle interior noise is mainly caused by irregularity of road, engine and transmission. So it is important to study on the noise characteristics for diesel engine and identify the main noise source and investigate the effective methods to control noise. In this paper, by using the measurement and analysis system, we measured the sound pressures levels and their curves the noise of a military diesel engine, then made spectral analysis and coherence analysis. The results provide bases for low noise design of this diesel engine.

scholarly journals Analysis of Skid Resistance and Noise Characteristics for Varieties of Concrete Pavement

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jinmiao Fang ◽  
Jinsong Tu ◽  
Kunming Wu
Keyword(s):  
Noise Level ◽  
Evaluation Criteria ◽  
Sound Intensity ◽  
Low Noise ◽  
Concrete Pavement ◽  
Skid Resistance ◽  
Concrete Pavements ◽  
Noise Levels ◽  
Cement Concrete ◽  
Noise Characteristics

To establish evaluation criteria for the pavement skid resistance and noise level in tunnels pavements, the zoning and control standards for skid resistance and concrete pavement noise were examined. Transverse friction coefficient (TFC) test equipment and the on-board sound intensity (OBSI) method were used to evaluate the antisliding characteristics and noise levels of several tunnel pavements. The results indicated poor antisliding characteristics and noise levels in ordinary grooved cement concrete pavement, whereas new types of cement concrete pavements, such as exposed concrete pavements and polymer-modified cement concrete pavements, had good antisliding characteristics and achieved low noise levels. Combined with the cluster analysis method, a zoning method for the antisliding and noise level in concrete pavement is proposed. The antisliding characteristics and noise levels of the pavement are divided into three zones. To ensure safety and comfort during driving, the antisliding value (SFC) of the tunnel pavement should be more than 50, and the noise level should not exceed 105 dB. Finally, the correlation between the antisliding and noise levels for pavement was analyzed. The results indicated that the antiskiding value of pavement has a strong correlation to the noise level.

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