Lapse Time Research Articles

Evidence of spatial variations of attenuation in the western Pyrenean range

Summary. Spectral attenuation of coda waves has been studied in the range 2-40 Hz from local events recorded in the western Pyrenean range from 1980 to 1982. Q, was obtained using a single scattering model ol' S-waves for different segments of the coda. An increase of Q, with lapse time was found and attributed to a rapid increase of Qp with depth. Three groups of events were selected from distinct focal areas. Two data sets are mainly composed of aftershocks of moderate earthquakes of magnitude 5.1 and 4.8, respectively. No moderate earthquake occurred in the third area in the few years preceding or following the selected events. Use of stations close to epicentres allowed sampling of the coda at very short lapse times and then study of small, distinct scattering volumes. Noticeable differences were found between the three studied areas and attributed to spatial rather than temporal variations. The Q, frequency dependence was studied according to Q, = qfa. (Y is found to range from 0.7 to 1.1 and q from 30 to 140. These values are in agreement with those found inother tectonic areas. It is shown that scattering is the dominant attenuation process below 10 Hz.

Magnitude‐frequency relation for small earthquakes: A clue to the origin of ƒmax of large earthquakes

In order to test the hyothesis that the ƒmax of large earthquakes is due to the source effect and is causally related to the corner frequency of small earthquakes when it becomes constant below magnitude about 3, we constructed the frequency‐magnitude relation for earthquakes with magnitude range from −1/3 to 4 recorded at a borehole seismograph station operated by the University of Southern California at Baldwin Hills in the middle of the Newport‐Inglewood fault. A procedure was developed for an accurate estimation of moment magnitude from the measurement of coda amplitude as a function of lapse time. The cumulative number of earthquakes per unit time period and area was estimated by finding the detection limit for ts‐p for each magnitude. We found a clear depature of the observed log frequency‐magnitude relation for M < 3 from the linear relation extrapolated from the data for M > 3. The observed frequency of earthquakes with M ≃ 0.5 is almost 10 times less than that expected from the extrapolation of empirical relation for earthquakes with magnitudes larger than 3. We conclude that the observed frequency‐magnitude relation departs from self‐similarity for earthquakes with magnitude smaller than about 3. This departure coincides with the widely observed departure of the moment‐corner frequency relation from self‐similarity. These observations are consistent with the interpretation of ƒmax of large earthquakes in terms of the slip‐weakening instability model in which the critical slip may be a few tenths of a meter to a few meters and the cohesive zone size may be a few hundred meters to a few kilometers.

A precursorlike change in coda excitation before the Western Nagano Earthquake (Ms = 6.8) of 1984 in central Japan

Temporal variations of coda duration were studied in relation to a crustal earthquake (September 14, 1984) which took place near the NW corner of the Kanto‐Tokai microearthquake observation network of the National Research Center for Disaster Prevention in Japan. Vertical seismograms recorded at station GER close to the main shock epicenter (Δ = 24 km) between February 1982 and December 1984 were analyzed. A precursorlike change was found in the relation between coda duration and average magnitude for 185 earthquakes which occurred in a small volume in the middle of the aftershock region. The average magnitude is the arithmetic mean of station magnitudes which are calculated from the maximum amplitudes of direct waves. Coda durations for earthquakes of the same average magnitude were significantly longer during the 16‐month period preceding the main shock than those before and after this period with a confidence level of 99.9%. The increase in coda durations was about 3 s on average in this period. The coda duration anomaly was significant for lapse time shorter than 30 s, which corresponds to a travel radius less than ∼50 km. Although no clear temporal change was found in the residuals of station magnitude measured at GER from average magnitude, an attenuation change in the preevent period can not be ruled out due to the large scatter of data. Crack formation, however, is the most plausible mechanism for an increase in scattering intensity around the focal region in the stress accumulation stage and is consistent with other precursory observations. Clusters of cracks in the heterogeneous earth medium might be big enough to scatter high‐frequency seismic waves, even though each individual crack may be very small.

Parameter values for snowmelt runoff modelling

Parameters which appear frequently in snowmelt runoff models are analyzed with the aim of facilitating their evaluation. Results of runoff computations by the Snowmelt Runoff Model (SRM) carried out at various institutes, universities and agencies on 24 basins ranging in size from 0.77 to 4000 km 2 and in elevation from 171 to 6000 m a.s.l. from 11 countries are reviewed. Based on this review, the physically and hydrologically understandable range of parameter values is assessed for the degree-day factor, runoff coefficient, temperature lapse rate, critical temperature (rain-snow), time lag, and recession coefficient. Consideration of SRM parameter values in these past applications may prove valuable for SRM applications on other basins and for initial selection of related parameter values in other snowmelt runoff models.

Estimates of seismic wave attenuation in northern Baja California

AbstractBy applying the spectral ratio method and the coda wave theory of Aki and Chouet (1975) to digital records of microearthquakes in Baja California, we have determined the seismic quality factors Qα, Qβ independent of frequency, and Qc(f) and Qβ(f) as a function of frequency. We found that Qα and Qβ, independent of frequency and in the range from 3 to 25 Hz, increase with the difference in epicentral distance between two stations. At short distances (∼ 16 km), Qβ is approximately 65, and at longer distances (∼83 km), Qβ increases to 700. We obtained only three values of Qβ/Qα (1.11, 1.47, and 0.87).Qc(f) and Qβ(f) were calculated from events recorded around the San Miguel fault at distances not greater than 30 km and source depths between 5 and 15 km. Qc(f) = (37 ± 13)f0.87±0.04 was found in the range of frequencies from 3 to 24 Hz. We found that the minimum mean free path was almost constant (15 km) for the range of frequencies analyzed. Determinations of Qβ(f) were performed using two lapse times. At short lapse time (10 sec), Qβ(f) was almost linear with frequency, increasing from 43 at 3 Hz to 392 at 24 Hz [Qβ(f) = 13f1.03]. These values correspond to near-surface attenuation. On the other hand, at relative long lapse time (16 sec), Qβ(f) increases from 147 at 3 Hz to 625 at 24 Hz [Qβ(f) = 70f0.74]. These last values of Qβ(f) are within the range of variation of Qc(f).

Variations of Monomethylhydrazine Content in Gyromitra esculenta

Monomethylhydrazine (MMH), a toxic constituent of Gyromitra esculenta, has been titrated according to the harvest site, the lapse time prior to analysis, and the different ways of preservation of the ascocarps. Thus, Gyromitras collected at a middle attitude are richer in MMH than those collected at high altitude. Desiccation for more than one month at room temperature yields the lowest amounts of MMH. A prolonged desiccation resulted in the MMH proportion stabilizing around values which correspond with a stable and non-volatile combination of the hydrazine in the fruit body. Freezing and then thawing activate the liberation of MMH. Moreover, this hydrazine has been identified for the first time in other Helvellaceae and in Geoglossaceae.

Variations of Monomethylhydrazine Content in Gyromitra Esculenta

Monomethylhydrazine (MMH), a toxic constituent of Gyromitra esculenta, has been titrated according to the harvest site, the lapse time prior to analysis, and the different ways of preservation of the ascocarps. Thus, Gyromitras collected at a middle attitude are richer in MMH than those collected at high altitude. Desiccation for more than one month at room temperature yields the lowest amounts of MMH. A prolonged desiccation resulted in the MMH proportion stabilizing around values which correspond with a stable and non-volatile combination of the hydrazine in the fruit body. Freezing and then thawing activate the liberation of MMH. Moreover, this hydrazine has been identified for the first time in other Helvellaceae and in Geoglossaceae.

Attenuation of coda waves in New England

Abstract Seismic wave attenuation was measured in New England from the time domain decay of coda wave amplitudes on narrow bandpass-filtered seismograms of local earthquakes. The frequency band of interest was 0.75 to 10 Hz. Q c ( f ) was found to increase with frequency across this band, but there was also a difference between the Q c ( f ) values for short ( t t > 100 sec) lapse times of coda wave propagation. For the short-lapse time data, corresponding to wave paths primarily in the upper crust, Q c ( f ) increases from 400 at 3 Hz to 1300 at 10 Hz. For the large-lapse time data, corresponding to wave paths in the lower crust and upper mantle, Q c ( f ) was found to vary from 660 at 1 Hz to 1500 at 10 Hz. If we interpret this dataset in terms of a model incorporating both scattering and anelastic attenuation, we find that the mean free path of seismic waves over this frequency band is 80 km for short-lapse times, and 400 km for long-lapse times. If we assume that scattering is entirely responsible for the observed attenuation, we find that the minimum mean free path for short-lapse times is about 75 km over all frequencies, whereas for long-lapse times, the minimum mean free path decreases from 400 km at 0.75 Hz to 90 km at 10 Hz.

Characteristics of coda waves: Central and southcentral Alaska

Abstract Code amplitude decay rates as a function of lapse time (time measured from the origin time) for two moderate size Alaskan earthquakes are related to their known values of seismic moments. This relation is then used to compute seismic moments from coda-wave data for a selected group of small earthquakes located in the greater Fairbanks, Alaska, seismic zone. The computed values of moment appear to be consistent with the local magnitudes. Next, with the moment and magnitude data, an empirical moment-magnitude relation is obtained for central and southcentral Alaska. This relation is similar to those for central and northern California proposed by others. Computation for Q values in the frequency ( f ) band 1.03 to 1.5 Hz for central and southcentral Alaska with local coda-wave data yielded values in the range from about 160 to 290. The minimum of Q(f) appears to be in the frequency interval from 0.5 to 1.5 Hz. Moreover, Q values ( f = 1 Hz) in the above range have been recently reported by others for areas in western United States having similar tectonic history as the Alaskan study area.

Comparison of the effects between single and multiple scattering on coda waves for local earthquakes

The effects of multiple scattering on coda waves have been investigated by an extension of the single-scattering theory. The contributions to the coda power due to multiple scattering from a uniform distribution of isotropic scatterers in a two-dimensional infinite elastic medium have been numerically evaluated. The results show that at shorter lapse time, the coda power is well explained by the single-scattering theory. At longer lapse time, the effects of multiple scattering need to be considered. The neglect of multiple scattering gives rise to an overestimation of the values of the quality factor ( Q ) by a factor of 1.4.

Effects of multiple scattering on coda waves in three-dimensional medium

The contribution of multiple scattering to the coda waves for three-dimensional elastic medium is investigated by extending the computational procedures developed earlier for the two-dimensional medium. It is shown that the effects of multiple scattering start to become important at a shorter lapse time,tc = 0.65(n0σu)−1, than in the two-dimensional case (tc = 0.8(n0σu)−1).

A Miniature Instrument for Residual Stress Measurement

AbstractThe Pennsylvania State University has developed and tested a miniature x-ray instrument for the measurement of residual stress (strains). The stress head including x-ray source and detection surface is approximately four and one-half inches long and can be inserted into an orifice less than two and one-half inches in diameter. This head is on the end of a several-foot long cable and is extremely manipulatable.The instrumentation design is based upon a unique position sensitive scintillation detector which ie capable of applying the single-exposure x-ray stress measurement technique. Total lapse time data collection periods for aluminum alloys are less than ten seconds with x-ray tube powers of 120 watts. Results from a four-point bend test on an aluminum alloy specimen showed excellent precision. The configuration of the instrument and the procedures for its application are described.

Coda wave excitation due to nonisotropic scattering and nonspherical source radiation

Under the assumption that seismic coda waves may be modeled as a superposition of single scattered body waves due to scatterers randomly distributed in the three‐dimensional earth, we study how nonisotropic scattering and nonspherical source radiation patterns affect the coda wave excitation. The energy density of coda waves is represented by an integral over scattering angle or radiation angle. Properties of each integral kernel are analytically studied in detail. The energy density of coda waves is factored into 2 parts: a geometrical spreading factor and a function of the ratio of the lapse time measured from the earthquake origin time to the travel time of direct wave. The equations predict that the influence of nonisotropic scattering and that of nonspherical source radiation will be significant, particularly on the early part of coda waves.

Attenuation of shear-waves in the lithosphere for frequencies from 0.05 to 25 Hz

Q for shear-waves in the crust and upper mantle was determined as a function of frequency in the range 1–25 Hz, using band-pass filtered records of about 900 earthquakes occurring in the central Japan area with focal depths from 0 to 150 km. The data were supplied from two stations in the Kanto region, operated by the Earthquake Research Institute, University of Tokyo. The method is taken from Aki and Chouet (1975) and Rautian and Khalturin (1978), and is based on elimination of the source effect from observed spectra of shear-waves, by taking the ratio of their amplitudes to those of coda-waves (measured at a fixed lapse time). The effect of radiation patterns is removed by averaging the ratio over many events. The experimental procedure uses basically a single-station method, and its validity was confirmed by the agreement between results obtained from station Tsukuba and those from Dodaira. We found that Q shows a strong dependence on frequency: Q increases with frequency f proportionally to f n , where n was found to be 0.8 in the northeastern part of Kanto (area A), and 0.6 in the rest of the region (areas B + C). Previously, a value for n of 0.5 had been determined for the Garm area in central Asia by Rautian and Khalturin. In general, our results agree with those of Fedotov and Boldyrev (1969), who obtained values of n around 0.6 for the Kuril-Islands, using a single-station method based on assumptions more restrictive than those adopted here. Q values for the lithosphere have been estimated by various workers using surface-waves with periods greater than 15 s. If we combine the results from surface-waves with those obtained from the S- to coda-amplitude ratio, we find that the frequency-dependence of Q −1 is similar to that obtained from a simple relaxation model, with the peak somewhere around 0.5 Hz.

Relationships Among Question Level, Response Level and Lapse Time: Secondary Science

Relationships Among Question Level, Response Level and Lapse Time: Secondary Science

延繩によるマグロの釣獲時刻について

In order to clarify the time of capture of tunas by the long-line gear, the catch data and the records of capture that was measured by an automatic depth meter were examined. The experiments were carried out in the tropical Pacific for bigeye and yellowfin from January to March, 1974, and in the western South Pacific for albacore in November, 1969. Assuming that tuna catch is in proportion to the soaking time of the long-line gear, the CPUE/hour (soaking time) was estimated from the CPUE by soaking time. The lethal time (lapse time from capture to death) was calculated from the CPUE of dead fish by soaking time. The lethal times of bigeye, yellowfin and albacore were 4.82, 2.90 and 2.57 hours (soaking time), respectively. The CPUE/hour of live fish could be estimated by the lethal time. Then, comparisons of the variances and means of these CPUE/hour were made between daytime and nighttime. The bigeye showed greater values than the yellowfin not only in the lethal time but also in the variance of CPUE of dead fish. Accordingly, from pooled CPUE/hour of live and dead fishes in the bigeye and from the CPUE/hour of live fish in the yellowfin, it was considered that the feeding in the daytime is more active than that in the nighttime. In the albacore, the catch data in the nighttime was insufficient, but it was presumed that the feeding is of a similar tendency to the former species.

Question and Response Levels and Lapse Time Intervals

AbstractOne hundred and eighty question-response diads were obtained from taped sessions of eleven elementary teachers interacting with a group of their students. Teachers had been trained in asking questions at higher levels on the Bloom taxonomy and had been sensitized to the critical problem of allowing students time to consider questions and formulate answers. The lapsed time between the end of the teacher’s question and the beginning of the student’s response was determined for each diad. Each question and each response was classified by level on the Bloom scale (3). It was found that lapse time differs by question level and by response level, but that lapse time does not increase directly with the hierarchial level of the question or the response. A strong relationship between the question level and the level of cognitive functioning of the elementary student as reflected in his level of responding was found.

An Investigation of Relationships Among Question Level, Response Level and Lapse Time

An Investigation of Relationships Among Question Level, Response Level and Lapse Time

The significance of the human corpus luteum in pregnancy maintenance: I. Preliminary studies

Following the total removal of luteal tissue circulating plasma progesterone, intrauterine pressure, oxytocin response, and clinical progress in abortion have been determined sequentially in 12 first-trimester pregnant patients. Three patients were ovariectomized for the removal of ovarian cysts and 9 patients were luteectomized during tubal ligation in an attempt to terminate pregnancy in spontaneous abortion. Seven patients had corpora lutea which averaged 21 ± 1 mm. in diameter at operation when performed at Day 49 ± 2 (mean S.E.) of pregnancy. These patients responded to ovariectomy or luteectomy by a continuing decrease in progesterone, evolution in intrauterine pressure and oxytocin response, progress in cervical dilatation, and abortion. Abortion occurred with a mean lapse time of 5±1 days after operation. In contrast, 5 patients whose corpora lutea averaged only 11 ±1 mm. in diameter when removed at Day 61 ± 4 of pregnancy showed only transient decrease in progesterone after operation. This decrease was followed by an increase in progesterone; no progress in the evolution of intrauterine pressure, oxytocin response, cervical dilatation, and abortion. It appears that so long as the corpus luteum serves as the major source of progesterone, it is indispensable in the maintenance of pregnancy in human subjects as it is in the clinical model animal, the rabbit. However, with the shift of progesterone production from the corpus luteum to the placenta (the luteoplacental shift) the human corpus luteum becomes dispensable. These findings identify the corpus luteum and its secretory product, Progesterone, as feasible targets of fertility control strategy.

Effect of Ronnel on the respiration rate of Ornithodoros savignyi ticks at different temperatures after topical application or oral ingestion.

The metabolic rate of unfed Ornithodoros savignyi females was determined at different temperatures. Oxygen consumption steadily increased from 15° to 35°C (Q10 = 2.6). At 35°C a plateau began, indicating no further increase in the external respiration rate in spite of a temperature increase to 40° and 45°C. These temperatures also markedly shortened the longevity of the ticks. Daily changes in weight and external respiration rates were determined for O. savignyi females after (1) topical application of 200 μg ronnel (an organophosphate pesticide) and maintenance at the constant temperatures 15°, 25°, 35° and 45°C and at 80% RH, (2) feeding on a rat which had received ronnel orally, and (3) direct ingestion of the pesticide by the tick through an artificial membrane with a blood meal. All ticks exposed topically ultimately died showing a peak in oxygen consumption of a 4 to 5-fold magnitude up to several days after application, longer periods occurring at lower temperatures. Even at 35°C the lapse time was 2–1/2 days, while at the adverse temperature of 45°C it occurred a day following exposure. A temperature of 15°C was generally too low for effective absorption and metabolism of the pesticide, but significant amounts remained available to the exposed ticks for at least 20 days. At all temperatures appreciable weight loss occurred during the hours of peak oxygen consumption. At 25°C some ronnel was absorbed immediately through the cuticle of topically-exposed ticks, but even after 4 or 5 days at either 25° or 35°G substantial external amounts of the pesticide persisted. Ronnel circulating in the blood of a rat at 3 ppm at the time of tick feeding did not affect the respiration rate or longevity of the ticks. Other ticks which had engorged through an artificial membrane on blood containing pesticide at the rate of 100 mg ronnel/kg blood showed, after engorgement, a steady increase in respiration rate at 25°C compared with a steady decline in the rate of control ticks, but none died. Ronnel was expelled with the coxal fluid by ticks held at 25°C during the first hour and up to 20 hr following ingestion with the blood meal.