Seafloor Erosion induced by overbanking flow derived by a 2.5D high resolution sparker seismic dataset, uppermost Kaoping Submarine Canyon, southwestern offshore Taiwan

2020 ◽  
Author(s):  
Wei-Chung Hsiao ◽  
Yi-Ching Yeh ◽  
Yen-Yu Cho ◽  
Shu-Kun Hsu
Keyword(s):  
River Mouth ◽  
Seismic Source ◽  
Submarine Canyon ◽  
Point Of View ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Match Filter ◽  
The North ◽  
Manila Trench ◽  
Marine Seismic

<p>The Kaoping submarine canyon (KPSC) originates from Kaoping River, southwestern Taiwan that extends about 250 kilometers long from the Kaoping River mouth down to the Manila Trench. It can be divided into three major sections: upper reach (meandering), middle reach (NW-SE trending and V-shaped canyon) and lower reach (meandering). Based on recent a swath bathymetric data in the uppermost KPSC, an obvious seafloor depression can be observed in the eastern bank of the canyon. The eastern bank of the canyon reveals about 30-50 meters in average lower than western bank. The mechanism is blurred. In this study, to investigate fine sedimentary structures in 3D point of view, we used marine sparker seismic method. The seismic source frequency varies from 100 to 1200 Hz which can provide about 0.6 meters vertical resolution (i.e. central frequency 600 Hz and 1,600 m/s Vp). We have collected 75 in-lines across the canyon and 3 cross-lines perpendicular to the in-line. The data went through conventional marine seismic data processing procedures such as bad trace kill, band-pass filter, 2D geometry settings, NMO stacking, swell correction, match filter and predictive deconvolution. The 2D dataset was reformatted by applying 3D geometry settings to create a 3D seismic cube. The result shows that a wide incision channel was first found in the north of Xiaoliuchiu islet. Through depth, this channel becomes two narrower channels divided by a mud diapir. This down cutting can be traced down to transgressive sequence in prior to LGM (Last Glacial Maximum). In addition, a deep-towed sub-bottom profiler shows an obvious down-lapping structures heading off canyon that indicates over banking flow may be a key role to cause this erosional event.</p>

PC‐based acquisition and processing of high‐resolution marine seismic data

Geophysics ◽  
1996 ◽  
Vol 61 (6) ◽  
pp. 1804-1812 ◽  
Author(s):  
Ho‐Young Lee ◽  
Byung‐Koo Hyun ◽  
Young‐Sae Kong
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Spectral Characteristics ◽  
Processing System ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Optical Disk Drive ◽  
Air Gun ◽  
Marine Seismic

We have improved the quality of high‐resolution marine seismic data using a simple PC‐based acquisition and processing system. The system consists of a PC, an A/D converter, and a magneto‐optical disk drive. The system has been designed to acquire single‐channel data at up to 60,000 samples per second and to perform data processing of seismic data by a simple procedure. Test surveys have been carried out off Pohang, southern East Sea of Korea. The seismic systems used for the test were an air gun and a 3.5 kHz sub‐bottom profiling system. Spectral characteristics of the sources were analyzed. Simple digital signal processes which include gain recovery, deconvolution, band‐pass filter, and swell filter were performed. The quality of seismic sections produced by the system is greatly enhanced in comparison to analog sections. The PC‐based system for acquisition and processing of high‐resolution marine seismic data is economical and versatile.

scholarly journals North Atlantic midwinter storm track suppression and the European weather response in ERA5 reanalysis

2021 ◽  
Author(s):  
Estefania Montoya Duque ◽  
Frank Lunkeit ◽  
Richard Blender
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Storm Track ◽  
Reanalysis Data ◽  
Band Pass Filter ◽  
Pass Filter ◽  
The North ◽  
Temperature And Precipitation ◽  
Precipitation Increase ◽  
Precipitation Anomalies

AbstractIn this study, we analyse the influence of North Atlantic midwinter storm track suppressions on European synoptic temperature and precipitation anomalies to determine the large-scale conditions relevant for the so-called Christmas thaw. We diagnose this relation in daily ERA5 reanalysis data in the spatial resolution of 0.25∘ between 1979 and 2018. To access synoptic time scales, a 3–10-day band-pass filter is applied. An index for the suppression is defined by the upper tropospheric Eddy Kinetic Energy (EKE) anomalies in the North Atlantic. We define the strong jet stream years as the year exceeding the 75% of the winter seasonal values at 250 hPa. In winters with strong jet activity, the storm track suppression is found, in agreement with the barotropic governor mechanism. Composites of European surface temperature and precipitation for low index values reveal weakly warmer conditions during winter (DJF) in Central Europe and the British Isles and a distinct cooling in Northern Europe. In the 1-month interval during December 15 to January 15, the warming is more pronounced. The clearest signal is the precipitation increase with a magnitude of 1 mm/day in the Mediterranean region.

PROCESSING OF MARINE SEISMIC DATA FROM AREAS WITH LARGE AND RAPID VARIATION IN WATER DEPTH

1971 ◽  
Vol 11 (1) ◽  
pp. 95
Author(s):  
Al Sabitay
Keyword(s):  
Seismic Data ◽  
Bottom Topography ◽  
Computer Programs ◽  
Bottom Surface ◽  
Band Pass Filter ◽  
Process Data ◽  
Rapid Variation ◽  
Pass Filter ◽  
Marine Seismic ◽  
Water Bottom

The offshore search for oil and gas is progressively moving further out to sea as near-shore structures are delineated and drilled. Prospects that overlap the edge of the continental shelf and slope will more than likely present problems in the processing of marine seismic data because of large and rapid variation in water depth.Magellan Petroleum encountered such difficulties in the digital computer processing of its East Gippsland Basin Prospect which is located some 50 miles southeast of the Victoria coastline.A series of problems developed when an integrated computer program sequence or "package" was applied to the data. It was found that first break suppression schedules, deconvolution design gates, band-pass filter application gates and velocity functions could not be changed often enough due to program restrictions.Where the water bottom topography was rough, the restriction of submitting only three or four water depths to vary the velocity function and subsequent calculation of normal move-out corrections resulted in questionable accuracy for the corrected results.Sometimes, water bottom variations required individual trace static corrections which were not available in this particular "package" processing.Water bottom multiple periods vary as rapidly as the surface that generates them. A meticulous selection of the parameters of deconvolution programs is necessary to attenuate multiples under such conditions. Also close examination of the purposes and consequently methods of deconvolution computer programs is necessary to maximize the effectiveness of this powerful processing tool.Diffractions are frequently generated at points on an irregular sea bottom surface. Such detractions mask true water bottom reflections in deeper water and thus decrease the geophysicist's ability to process data accurately where computer programs require true water bottom depth.Presentation of record sections which illustrate problems and their probable solutions comprise a major part of this paper.

scholarly journals Decoupling Hypothesis and the Financial Crisis

2013 ◽  
Vol 4 (3) ◽  
pp. 25-40
Author(s):  
Joanna Wyrobek ◽  
Zbigniew Stańczyk
Keyword(s):  
Emerging Economies ◽  
Point Of View ◽  
Gdp Growth ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Term Trend ◽  
Advanced Economies ◽  
Band Pass ◽  
Long Term Trend

The purpose of this paper was to present the decoupling hypothesis which says that the performance of emerging economies becomes relatively independent of the changes in advanced economies, and to empirically verify this hypothesis. The Christiano-Fitzgerald band-pass filter and spectral analyses have been applied to examine the hypothesis. On the basis of obtained results, comparing the deviations of GDPs from their long-term trend, it seems that the synchronization of cycles between emerging and advanced economies was already high before the crisis. The last global crisis, especially if time shifts between the countries are taken into account, even increased the synchronization of the economies. Therefore, this paper presents evidence against the decoupling hypothesis, and at the same time it raises doubts whether the high GDP growth rates in emerging economies can be sustainable in the presence of the slow-down in the advanced economies. The paper analyzes the situation from the Poland’s point of view as the country which is on the verge of joining the ERM2 system and adopting the euro (synchronization divagations are important for this decision) and because Poland is a good example of an emerging economy.

scholarly journals ACOUSTIC DETECTION AND CHARACTERIZATION OF MARINE SEDIMENT WITH SHALLOW SEISMIC TECHNOLOGY IN RAMBAT WATERS, BANGKA BELITUNG

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Haqqu Ramdhani ◽  
Henry M. Manik ◽  
Susilohadi Susilohadi
Keyword(s):  
Gain Control ◽  
Data Interpretation ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Reflection Seismic ◽  
Illegal Mining ◽  
Predictive Deconvolution ◽  
Band Pass ◽  
Marine Seismic ◽  
Seafloor Sediment

<p>High resolution of marine seismic reflection seismic were used to detect the layers of seafloor sediment and to interpret the seismic data geologically. The objectives of this study weres to detect and to characterize the seafloor sediment in the Rambat area, West Bangka, Bangka Belitung. Acquisition data was held on 10-24  August  2012 located between 105.1°00'00" - 105.5°00'00 " N and 1.7°00'00"-1.9° 00'00" W. Several methods used to process the data were geometry processing, band pass filter, predictive deconvolution,  and Autocoralation Gain Control (AGC)  in order to reduce the multiple noise and to  ease the data interpretation. Seismic cross section found in Cross Rambat (CRMBT) line 11 exhibited  sedimentation process of the sea floor which rocky substrates. The process was assumed to be occurred due to legal and illegal mining activities for long period of time.</p> <p>Keywords: seismic, acoustic, sediment, band pass filter, deconvolution, noise</p>

scholarly journals ACOUSTIC DETECTION AND CHARACTERIZATION OF MARINE SEDIMENT WITH SHALLOW SEISMIC TECHNOLOGY IN RAMBAT WATERS, BANGKA BELITUNG

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Haqqu Ramdhani ◽  
Henry M. Manik ◽  
Susilohadi Susilohadi
Keyword(s):  
Gain Control ◽  
Data Interpretation ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Reflection Seismic ◽  
Illegal Mining ◽  
Predictive Deconvolution ◽  
Band Pass ◽  
Marine Seismic ◽  
Seafloor Sediment

High resolution of marine seismic reflection seismic were used to detect the layers of seafloor sediment and to interpret the seismic data geologically. The objectives of this study weres to detect and to characterize the seafloor sediment in the Rambat area, West Bangka, Bangka Belitung. Acquisition data was held on 10-24  August  2012 located between 105.1°00'00" - 105.5°00'00 " N and 1.7°00'00"-1.9° 00'00" W. Several methods used to process the data were geometry processing, band pass filter, predictive deconvolution,  and Autocoralation Gain Control (AGC)  in order to reduce the multiple noise and to  ease the data interpretation. Seismic cross section found in Cross Rambat (CRMBT) line 11 exhibited  sedimentation process of the sea floor which rocky substrates. The process was assumed to be occurred due to legal and illegal mining activities for long period of time. Keywords: seismic, acoustic, sediment, band pass filter, deconvolution, noise

scholarly journals Response envelope spectrum and interpretation of strong earthquake ground motion

1971 ◽  
Vol 61 (2) ◽  
pp. 343-356 ◽  
Author(s):  
M. D. Trifunac
Keyword(s):  
Ground Motion ◽  
Strong Earthquake ◽  
Structural Engineering ◽  
Point Of View ◽  
Earthquake Ground Motion ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Band Pass ◽  
Envelope Spectrum ◽  
Response Envelope

abstract A multiple filter technique is developed using a single-degree-of-freedom lightly-damped oscillator as a narrow band-pass filter. It provides for a physically simple approach to the analysis of accelerograph records from the point of view of structural engineering. The analysis of several typical accelerograph records indicates that a significant portion of strong earthquake ground motion consists of surface waves. It is concluded that the duration of intense shaking will be determined predominantly by the dispersion properties of the ground.

Past Verses Present; Metamorphosis in Different Spheres of Guwahati: A Study of Srutimala Duara’s Mindprints of Guwahati

2020 ◽  
Vol 8 (2) ◽  
pp. 13
Author(s):  
Ankita Pandey
Keyword(s):  
Point Of View ◽  
Areca Nut ◽  
Medieval Period ◽  
River Bank ◽  
North East India ◽  
North East ◽  
The North ◽  
Indian State ◽  
The City ◽  
Beautiful City

Guwahati derives its name from the Assamese word “Guwa” means areca nut and “Haat” means market. However, the modern Guwahati had been known as the ancient Pragjyotishpura and was the capital of Assam under the Kamrupa kingdom. A beautiful city Guwahati is situated on the south bank of the river Bramhaputra. Moreover, It is known as the largest city in the Indian state of Assam and also the largest metropolis in North East India. It has also its importance as the gateway to the North- East India. Assamese and English are the spoken languages in Guwahati.  In 1667, the Mogul forces were defeated in the battle by the Ahom forces commanded by Lachut Barphukan. Thus, in a sense Guwahati became the bone of contention among the Ahoms, Kochas and the Moguls during the medieval period.  Guwahati the administrative headquarters of Lower Assam with a viceroy or Barbhukan was made by the Ahom king.  Since 1972 it has been the capital of Assam. The present paper will discuss the changes happened in Guwahati over the period of late 1970s till the present time. It will focus on the behavior of people, transformed temples, Panbazar of the city, river bank of Bramhaputra, old Fancy Bazaar, chaotic ways, festivals and seasons including a fifth man made season etc. It will also deal how over the years a city endowed with nature’s gifts and scenic views, has been changing as “a dirty city”. Furthermore, it will also present the insurgencies that have barged into the city. The occurrence of changes will be discussed through the perspective and point of view of Srutimala Duara as presented in her book Mindprints of Guwahati.

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