POSSIBLE P‐WAVE OBSERVATIONS IN SHORT‐PERIOD SEISMIC NOISE

Geophysics ◽  
1965 ◽  
Vol 30 (6) ◽  
pp. 1187-1190 ◽  
Author(s):  
A. J. Seriff ◽  
C. J. Velzeboer ◽  
R. J. Haase
Keyword(s):  
Seismic Noise ◽  
P Wave ◽  
Deep Hole ◽  
Frequency Range ◽  
The Past ◽  
Deep Well ◽  
Short Period ◽  
Noise Measurements ◽  
Deep Boreholes

For the past two years we have been engaged in a program of seismic noise measurements in deep boreholes; noise in a frequency range of approximately 0.2 to 5.0 cps has been studied. A special deep‐well seismometer designed by The Geotechnical Corporation has been used for recording noise at depths down to 14,000 ft in cased holes. The seismometer, which has a response almost identical to the typical short‐period Benioff, was clamped to the casing of the deep hole by a mechanical locking arm during observation periods. An identical seismometer has been used as a reference in a 500‐ft hole adjacent to the deep well. A surface array of four vertical Benioff seismometers was also recorded, with one seismometer near the well and three others at distances ranging from 0.5 to 1.0 km. Two horizontal seismometers were stationed near the wellhead.

Short-period seismic noise

1967 ◽  
Vol 57 (1) ◽  
pp. 55-81
Author(s):  
E. J. Douze
Keyword(s):  
Surface Waves ◽  
Rayleigh Waves ◽  
Seismic Noise ◽  
Body Waves ◽  
Deep Hole ◽  
Period Range ◽  
Short Period ◽  
The Subject ◽  
Hole Arrays

abstract This report consists of a summary of the studies conducted on the subject of short-period (6.0-0.3 sec period) noise over a period of approximately three years. Information from deep-hole and surface arrays was used in an attempt to determine the types of waves of which the noise is composed. The theoretical behavior of higher-mode Rayleigh waves and of body waves as measured by surface and deep-hole arrays is described. Both surface and body waves are shown to exist in the noise. Surface waves generally predominate at the longer periods (of the period range discussed) while body waves appear at the shorter periods at quiet sites. Not all the data could be interpreted to define the wave types present.

STANDING‐WAVE PHENOMENA IN SHORT‐PERIOD SEISMIC NOISE

Geophysics ◽  
1965 ◽  
Vol 30 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
Indra N. Gupta
Keyword(s):  
Steady State ◽  
Standing Wave ◽  
Seismic Noise ◽  
P Wave ◽  
Stratified Medium ◽  
Alternative Theory ◽  
Compressional Waves ◽  
Short Period ◽  
Wave Phenomena ◽  
Phase Spectra

Short‐period vertical seismometers are used in deep holes at several sites to obtain the change with depth in amplitude and phase spectra of short‐period seismic noise. Although the observed spectra can be explained by an arbitrary combination of several Rayleigh modes, an alternative theory is suggested here. An attempt is made to explain both amplitude and phase spectra of observed microseisms of period less than 6 sec in terms of standing‐wave phenomena caused by steady‐state plane harmonic compressional waves propagating vertically through a horizontally stratified medium. At most sites, the observed data indicate satisfactory agreement with the expected results. A considerable fraction of the short‐period noise may, therefore, be regarded as P‐wave noise propagating vertically from below.

SPECTRAL STUDY OF SHORT-PERIOD P-WAVES

1967 ◽  
Vol 4 (6) ◽  
pp. 1049-1063 ◽  
Author(s):  
Gabriel Leblanc ◽  
Benjamin F. Howell Jr.
Keyword(s):  
P Wave ◽  
Inverse Filtering ◽  
Frequency Range ◽  
P Waves ◽  
Quantitative Measurements ◽  
Short Period ◽  
Oscillatory Character ◽  
Quantitative Results ◽  
Almost All ◽  
Amplitude Level

The variability of 37 short-period P-wave spectra was studied. Amplitude level is affected by distance and crustal effects. Similarity of the over-all shape of the spectra is attributed to the source. An oscillatory character, present on almost all spectra, is related to the crustal effect. Acting as a mask, the crustal effect prevents quantitative measurements of the attenuation and of the radiation pattern. By an averaging of spectra, the crustal masking can be partly overcome, and an approximation of the spectrum of the pulse incident at the mantle-crust boundary obtained. Selected average spectra suggest that over the frequency range 0.4 to 0.9 cps, very little, if any, differential attenuation takes place. The use of crustal inverse filtering, difficult though it may be, seems required for any quantitative results.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

scholarly journals Landslide geometry and activity in Villa de la Independencia (Bolivia) revealed by InSAR and seismic noise measurements

Landslides ◽  
2021 ◽  
Author(s):  
Chuang Song ◽  
Chen Yu ◽  
Zhenhong Li ◽  
Veronica Pazzi ◽  
Matteo Del Soldato ◽  
...  
Keyword(s):  
Time Series ◽  
Seismic Noise ◽  
Slip Surface ◽  
Inversion Method ◽  
Subsurface Structures ◽  
Slip Surfaces ◽  
Landslide Volume ◽  
Noise Measurements ◽  
Landslide Body

AbstractInterferometric Synthetic Aperture Radar (InSAR) enables detailed investigation of surface landslide movements, but it cannot provide information about subsurface structures. In this work, InSAR measurements were integrated with seismic noise in situ measurements to analyse both the surface and subsurface characteristics of a complex slow-moving landslide exhibiting multiple failure surfaces. The landslide body involves a town of around 6000 inhabitants, Villa de la Independencia (Bolivia), where extensive damages to buildings have been observed. To investigate the spatial-temporal characteristics of the landslide motion, Sentinel-1 displacement time series from October 2014 to December 2019 were produced. A new geometric inversion method is proposed to determine the best-fit sliding direction and inclination of the landslide. Our results indicate that the landslide is featured by a compound movement where three different blocks slide. This is further evidenced by seismic noise measurements which identified that the different dynamic characteristics of the three sub-blocks were possibly due to the different properties of shallow and deep slip surfaces. Determination of the slip surface depths allows for estimating the overall landslide volume (9.18 · 107 m3). Furthermore, Sentinel-1 time series show that the landslide movements manifest substantial accelerations in early 2018 and 2019, coinciding with increased precipitations in the late rainy season which are identified as the most likely triggers of the observed accelerations. This study showcases  the potential of integrating InSAR and seismic noise techniques to understand the landslide mechanism from ground to subsurface.

RAPIDLY GROWING DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOR

Neurosurgery ◽  
2006 ◽  
Vol 59 (6) ◽  
pp. E1337-E1338 ◽  
Author(s):  
Oltea Sampetrean ◽  
Taketoshi Maehara ◽  
Nobutaka Arai ◽  
Tetsuo Nemoto
Keyword(s):  
Complex Form ◽  
Interesting Case ◽  
Labeling Index ◽  
Pathological Examination ◽  
Dysembryoplastic Neuroepithelial Tumor ◽  
Complex Partial Seizures ◽  
Ki 67 ◽  
The Past ◽  
Short Period ◽  
Postoperative Diagnosis

Abstract OBJECTIVE During the past 15 years, the concept of dysembryoplastic neuroepithelial tumors has continued to evolve. We present an interesting case of dysembryoplastic neuroepithelial tumor that showed rapid growth during a short period of time. CLINICAL PRESENTATION A 9-year-old boy had been experiencing intractable complex partial seizures since the age of 7 years. Magnetic resonance imaging scans demonstrated a well-demarcated 3.5-cm lesion with a 1.5-cm ring-enhanced core in the left temporal lobe. One month later, the lesion had rapidly grown to occupy three times more space than on the first evaluation, with the ring-enhanced core reaching approximately five times its initial volume. INTERVENTION A combined tumor removal and epileptogenic focus resection surgery was performed immediately. In the pathological examination, the presence of the specific glioneuronal element with a Ki-67 labeling index of lower than 1%, as well as the glial component with a Ki-67 labeling index of 8%, led to a postoperative diagnosis of dysembryoplastic neuroepithelial tumor, complex form. No adjuvant therapy was performed. Five years after surgery, there is no evidence of any recurrence and the boy continues to be seizure free without antiepileptic drugs. CONCLUSION The lesion did not behave as a stable benign entity as it is generally accepted, and is, therefore, presented as an argument in favor of an early and complete resection.

Short-period Lg magnitudes: Instrument, attenuation, and source effects

1983 ◽  
Vol 73 (6A) ◽  
pp. 1835-1850
Author(s):  
Robert B. Herrmann ◽  
Andrzej Kijko
Keyword(s):  
United States ◽  
Epicentral Distance ◽  
P Wave ◽  
Magnitude Scale ◽  
Source Effects ◽  
Anelastic Attenuation ◽  
Basic Conclusion ◽  
Short Period ◽  
Central United States ◽  
Definition Of

Abstract The applicaton of the Nutli (1973) definition of the mbLg magnitude to instruments and wave periods other than the short-period WWSSN seismograph is examined. The basic conclusion is that the Nuttli (1973) definition is applicable to a wider range of seismic instruments if the log10(A/T) term is replaced by log10A. For consistency and precision, the notation mbLg should be applied only to magnitudes based upon 1.0 Hz observations. The mbLg magnitude definition was constrained to be consistent with teleseismic P-wave mb estimates from four Central United States earthquakes. In general, for measurements made at a frequency f, the notation mLg(f) should be used, where m L g ( f ) = 2.94 + 0.833 log ⁡ 10 ( r / 10 ) + 0.4342 γ r + log ⁡ 10 A , and r is the epicentral distance in kilometers, γ is the coefficient of anelastic attenuation, and A is the reduced ground amplitude in microns. Given its stability when estimated from different instruments, the mLg(f) magnitude is an optimum choice for an easily applied, standard magnitude scale for use in regional seismic studies.

scholarly journals AT VENDE TILBAGE TIL UKENDTE STEDER - POSTHUKOMMELSE OG STED HOS JACOB DAMMAS, JACOB KOFLER OG MAJA MAGDALENA SWIDERSKA

1970 ◽  
Vol 42 (117) ◽  
pp. 113-130
Author(s):  
Anna Estera Mrozewicz
Keyword(s):  
Second Generation ◽  
Cultural Trauma ◽  
Documentary Films ◽  
The Past ◽  
Personal Stories ◽  
Short Period ◽  
Personal Approach ◽  
Personal Trauma ◽  
Related Identity ◽  
Theoretical Reflection

RETURNING TO UNFAMILIAR PLACES. PLACE AND POSTMEMORY IN THE WORKS OF JACOB DAMMAS, JACOB KOFLER, AND MAJA MAGDALENA SWI-DERSKA | The emigration of three thousand Polish-Jewish citizens to Denmark as a result of the events in March 1968 in Poland has only recently attracted attention from filmmakers and writers in Denmark. Two documentary films and a novel, created within a relatively short period of time, deal with the topic: Jacob Kofler’s Statsløs (Stateless), 2004, Jacob Dammas’ Kredens (Dresser), 2007, and Maja Magdalena Swiderska’s The Border Breaking Bunch, 2008. The authors are all children of refugees and represent second generation in relation to the cultural trauma of exile. The article examines aesthetic approaches developed by the authors as they (re)tell personal stories, which are mediated through various strategies of postmemory (Hirsch 1997). Postmemory is distinguished from memory by a non-indexical relation to the past and a generational distance, and from history by a highly personal approach. However, it is not addressed here as a psychological category. On the contrary, I argue that postmemory can be viewed as both an analytical and a narrative and aesthetic tool. Questions of place and place-related identity are relevant and inseparable from the three authors’ creative reimaginings of the cultural and personal trauma. Thus, the article focuses on the concepts of place and postmemory, and their interdependencies in the analysed works. Close readings are combined with theoretical reflection, which allows the objects and theories to illuminate each other.

Using relationship management to legitimate the monarchy: An analysis of the reign of King Juan Carlos I of Spain

2017 ◽  
Vol 14 (27) ◽  
Author(s):  
César García
Keyword(s):  
Public Support ◽  
Relationship Management ◽  
Mutual Benefit ◽  
Good Relationship ◽  
The Public ◽  
The Past ◽  
Short Period ◽  
Basic Relationship ◽  
High Level ◽  
New Democracy

This article explores the management of relationships by King Juan Carlos I of Spain to legitimate the monarchy as an institution and build a new democracy after Franco’s death in 1975. The high level of public support during most of his reign shows there is a correlation between good relationship management and the loyalty of the subjects. Only when some basic relationship management principles of mutual benefit, such as trust and openness with his subjects, were violated the level of support of Juan Carlos I, and the monarchy as an institution started to decline. Nonetheless, the value of relationship management has proved durable since the new monarch, Felipe VI, was able to recover in a relatively short period of time the public support that Juan Carlos I enjoyed in the past. This fact indicates that even in the case of disruptive monarchies, such as Spain, the power of relationship management has shown effectiveness to legitimate the institution. However, at the same time it also points out that in a public opinion regime monarchies have to show exemplarity and that involves not only to create mutual benefit for the citizenship through good deeds, since Juan Carlos I always behaved professionally as a business and diplomatic representative, but that there is feeling of trust between the monarch and the subjects.

Determination of source parameters of small earthquakes from P-wave rise time

1973 ◽  
Vol 63 (2) ◽  
pp. 599-614 ◽  
Author(s):  
M. E. O'Neill ◽  
J. H. Healy
Keyword(s):  
Rise Time ◽  
Source Parameters ◽  
P Wave ◽  
Simple Method ◽  
Zero Crossing ◽  
Basic Measurement ◽  
Earthquake Source Parameters ◽  
Short Period ◽  
Stress Drops

abstract A simple method of estimating source dimensions and stress drops of small earthquakes is presented. The basic measurement is the time from the first break to the first zero crossing on short-period seismograms. Graphs relating these measurements to rise time as a function of Q and instrument response permit an estimate of earthquake source parameters without the calculation of spectra. Tests on data from Rangely, Colorado, and Hollister, California, indicate that the method gives reasonable results.

Sign in / Sign up

Export Citation Format

Share Document