共查询到20条相似文献，搜索用时 31 毫秒
1.
J.A. Donato C.D. Honebon W.G.V. Rosser 《Physics of the Earth and Planetary Interiors》1973,7(2):161-166
The M2 (12.42-h period) magnetic field variation present at night in the United Kingdom can be interpreted in terms of sea tides, the main contribution being from the Atlantic Ocean. Osgood et al. (1970) observed a difference between the M2-variations in the total magnetic field (F) variations at Sidmouth (0.8 km from the coast) and Exeter (16 km from the coast) of amplitude 0.8 γ, which must be due to local effects. Analysis of the phase of this difference between Exeter and Sidmouth has shown that it cannot be due entirely to tidally induced electric current systems confined to the English Channel. Measurements with two three-component magnetometers have shown that the night-time variations in the north-south (H) component of 12.42-h period are significantly different at Sidmouth and Exeter. The difference in H is in phase with the expected electric potential difference across Devon due to the difference in the phases of the sea tides in the English Channel and the Bristol Channel. The results of Donato and Rosser (1973) on micropulsations suggest the existence of a region of high conductivity under Exeter. If this connects the English Channel to the Bristol Channel, a current will flow beneath Exeter giving a difference in the M2-variations in H at Exeter and Sidmouth. This difference in H dominates the M2-variations in the total magnetic field (F) variations at Exeter and Sidmouth measured by Osgood et al. (1970). 相似文献
2.
O. V. Sheremet’eva 《Geomagnetism and Aeronomy》2011,51(2):221-225
This work studies regular variations caused by the effect of O
1 and M
2 tidal waves on magnetospheric current systems. The response to the tidal effect has been calculated using the magnetic field
paraboloid model. A model of origination of the geomagnetic variations with O
1 and M
2 tidal wave periods has been developed. The values of such variations, which originate as a result of tidal deformations of
the current system in the magnetosphere, are 0.2÷0.9 nT. The calculated values coincide in magnitude with the processed geomagnetic
data obtained at the Paratunka geophysical observatory. 相似文献
3.
根据巴颜喀拉块体东部2011—2014年3期岩石圈磁场年变化情况,结合地壳应力资料,重点分析龙门山断裂带南段的岩石圈磁场变化与应力积累的关系。该区域2011—2012年和2012—2013年岩石圈磁场变化明显弱于周边区域,实测地壳应力结果反映汶川M_S8.0地震震后应力积累水平很高。压磁效应分析认为汶川M_S8.0地震后该区域高应力积累、低应变率的动力学背景是控制该区域岩石圈磁场弱变化的主要因素。此外,芦山M_S7.0地震及康定M_S6.3地震前震中区存在局部岩石圈磁场水平矢量的弱变化现象,尤其是2012—2013年水平矢量大小和方向均与周边区域相比存在明显差异,这可能是两次地震的前兆异常。 相似文献
4.
V. K. Milyukov A. V. Kopaev A. V. Lagutkina A. P. Mironov A. V. Myasnikov 《Izvestiya Physics of the Solid Earth》2007,43(11):922-930
Results of observations of tidal strains of the crust in the tectonically active Elbrus area of the Northern Caucasus carried out with the use of the Baksan SSAI laser interferometer strainmeter over the period from 2003 through 2006 are presented. Harmonic analysis is performed with the help of the ETERNA software package. Statistically significant time variations in the amplitudes of the main tidal waves M 2 and O 1 are revealed. The influence of the topography on tidal strains in the Baksan gorge is estimated at 22% (an increase in the measured strain values). The reduced amplitude factors of the main diurnal (O 1) and semidiurnal (M 2) waves are underestimated. Numerical modeling of tidal anomalies produced by regional heterogeneous inclusions is performed in a 2-D approximation. The observed anomaly of the M 2 wave (12%) is shown to be due to the influence of the main magma-controlling fault associated with the deep magma source of the Elbrus dormant volcano. 相似文献
5.
The hardware complex that was produced by OOO Polynom, Khabarovsk, for registration of the level, temperature, and electrical conductivity of ground water in wells and meteorological parameters (atmospheric pressure, air temperature) at a measurement frequency from 5 min to 1 h is described. The equipment is installed in the wells of Kamchatka and has been used for several years to register variations caused by earthquakes in the parameters of ground waters. Different variations in measured parameters of ground waters due to strong earthquakes of February 28, 2013, M W = 6.8 and May 24, 2013, M W = 8.3 are registered with this equipment in wells YuZ-5 and E-1. The registered variations and their systematization are described taking into account the mechanisms of a seismic impact on the state of the well–water-saturated rock system. 相似文献
6.
利用甘肃前兆台网观测资料进行时空扫描,发现地下流体参量、地倾斜等在甘肃酒泉金塔5.4级地震前10天内出现了一系列异常变化,鼎新—德令哈基线在两年半的时间内缩短5 mm;短临异常主要出现在距震中200km范围的台站,时间是3月中旬和4月下旬;临震异常集中出现的时间是4月28日至5月1日。距离震中较近的高台倾斜完整记录下酒泉金塔MS5.4地震发生过程中岩土石受力变化的全部过程,提供了地震孕育和发生的完整演化资料,对完善地震理论模型和地震预测有积极的研究价值。 相似文献
7.
D. M. Schlapp R. J. Stening J. M. Forbes A. H. Manson C. E. Meek R. A. Vincent 《Annales Geophysicae》1996,14(8):826-836
A numerical model has been used to calculate the atmospheric response to forcing at periods in the region of 12-13.5 h. The results show that the response is enhanced in the neighbourhood of 13 h. These results have been compared with lunar tidal analyses of mesospheric wind data and geomagnetic variations at a number of stations. It is found that the N2 lunar tidal component (period 12.66 h) is significantly enhanced relative to the main lunar tidal component M2 (period 12.42 h) in both types of data, compared with what would be expected from the gravitational tidal potential. This supports the predictions of the numerical model. An appreciable phase shift is also found in the experimental data between the N2 and M2 tides, agreeing in sense with what would be expected for a resonance at a period around 13 h. 相似文献
8.
This study examines connections between mean sea level (MSL) variability and diurnal and semidiurnal tidal constituent variations at 17 open-ocean and 9 continental shelf tide gauges in the western tropical Pacific Ocean, a region showing anomalous rise in MSL over the last 20 years and strong interannual variability. Detrended MSL fluctuations are correlated with detrended tidal amplitude and phase fluctuations, defined as tidal anomaly trends (TATs), to quantify the response of tidal properties to MSL variation. About 20 significant amplitude and phase TATs are found for each of the two strongest tidal constituents, K1 (diurnal) and M2 (semidiurnal). Lesser constituents (O1 and S2) show trends at nearly half of all gauges. Fluctuations in MSL shift amplitudes and phases; both positive and negative responses occur. Changing overtides suggest that TATs are influenced by changing shallow water friction over the equatorial Western Pacific and the eastern coast of Australia (especially near the Great Barrier Reef). There is a strong connection between semidiurnal TATs at stations around the Solomon Islands and changes in thermocline depth, overtide generation, and the El Niño Southern Oscillation (ENSO). TATs for O1, K1, and M2 are related to each other in a manner that suggests transfer of energy from M2 to the two diurnals via resonant triad interactions; these cause major tidal variability on sub-decadal time scales, especially for M2. The response of tides to MSL variability is not only spatially complex, it is frequency dependent; therefore, short-term responses may not predict long-term behavior. 相似文献
9.
《Continental Shelf Research》2006,26(17-18):2019-2028
Measurements of turbulence and suspended particulate matter (SPM) were measured over a 50 h period at a site in high tidal energy, mixed waters of the Irish Sea, NW European shelf. Turbulence parameters included both production (variance method from seabed ADCP) and dissipation (FLY profiler); SPM parameters included mass and volume concentrations and particle size (LISST 100 C). It is shown that the resultant SPM time series was due to a combination of time-varying turbulence at the measurement site and space-varying turbulence advecting through the site. Time asymmetry in turbulence at the site produced an asymmetric M4 signal in SPM volume concentration due to resuspension and disaggregation of flocs at times of peak turbulent energy. In terms of mass, the disaggregation contribution was 43% as much as the resuspension contribution near the bed, and 20% as much integrated throughout the water column. There was aggregation of flocs at high and low slack waters but the largest flocs occurred at low slack waters. Space-varying ambient turbulence was responsible for a horizontal gradient in floc size with small and large flocs at the high and low ends of the gradient, respectively; this generated a M2 signal in SPM properties. SPM concentrations and properties at any time resulted from combination of M2 and M4 variations which are responsible for the well-known twin peaks signature seen in transmissometer time series in tidal waters. 相似文献
10.
Semidiurnal tidal currents on the outer shelf of the Mackenzie Shelf in the Beaufort Sea were found to be strongly influenced by the locally generated baroclinic tide. Two primary factors are involved in this process: (1) the sharp shelf break along the northeastern Mackenzie Shelf, promoting the generation of vigorous internal tidal waves; and (2) the proximity to critical latitudes for M2 and N2 motions locking these waves and preventing them from leaving the source region. As a result, internal tides are resonantly trapped between the shelf and critical latitudes. The physical properties and temporal variations of tidal motions were examined using current meter measurements obtained from 1987–1988 at four sites (SS1, SS2, SS3, and SS4) offshore of the shelf break at depths of ∼200 m. Each mooring had Aanderaa RCM4s positioned at ∼35 m below the surface and ∼50 m above the bottom. Complex demodulation was used to compute the envelopes (amplitude modulation) of these components. A striking difference in the variability of clockwise (CW) and counterclockwise (CCW) tidal currents was found. The CW tides are highly variable, have greater amplitude, exhibit a burst-like character associated with wind events and contain about 80% of the total energy of the semidiurnal tidal currents. In contrast, the CCW components have a more regular temporal regime with distinct monthly, fortnightly and 10-day modulation at astronomical periodicities associated with frequency differences M2–N2 (0.03629 cpd), S2–M2 (0.06773 cpd), and S2–N2 (0.10402 cpd). Significant horizontal correlation of the CW current envelopes was found only between stations near the northeast Mackenzie Shelf, indicating this to be the main area of baroclinic internal wave generation. 相似文献
11.
The statistics of the relative variations (δfoF2) in the critical frequency of the ionospheric F 2 region during catastrophic earthquakes with magnitude M ≥ 6 at 70 vertical sounding (VS) automatic ionospheric stations (AISs) of the global network is considered. Five-day periods including 70 such situations have been selected for 1981 and 1983–1985. Five sets of 24 foF2 measurements from 3 days before to a day after the earthquake instant are formed for each AIS. The number of AISs, for which the fourth statistical invariant is above the significance level (E ≥ 1), has been analyzed. It has been indicated that the histogram deformation at the set of AISs is substantial a day before earthquakes. 相似文献
12.
以地震应变场作为地震活动的变量,通过自然正交函数展开方法,计算2017年8月8日四川九寨沟7.0级地震前的地震应变场,提取出震前时间因子的异常变化。计算结果发现应变场前4个时间因子在震前1~3年的中短期异常并不显著,只有第2个和第4个时间因子震前有小幅度的异常变化,分析其原因,时间因子可能受到2008年汶川8.0级地震和2013年岷县漳县6.6级地震前大幅度异常的影响。与时间因子对应的空间等值线形成局部应变高值异常危险区,可能是2013年岷县漳县6.6级地震和2017年九寨沟7.0级地震空间异常的中短期特征。再对比九寨沟7.0级地震前后与松潘-平武7.2级双震的空间异常随时间演变,分析异常发展变化模式的差异,最后应用地震资料的累积频次从物理角度解释异常形成的机制。 相似文献
13.
Starting from the classical empirical magnitude-energy relationships, in this article, the derivation of the modern scales
for moment magnitude M
w and energy magnitude M
e is outlined and critically discussed. The formulas for M
w and M
e calculation are presented in a way that reveals, besides the contributions of the physically defined measurement parameters
seismic moment M
0 and radiated seismic energy E
S, the role of the constants in the classical Gutenberg–Richter magnitude–energy relationship. Further, it is shown that M
w and M
e are linked via the parameter Θ = log(E
S/M
0), and the formula for M
e can be written as M
e = M
w + (Θ + 4.7)/1.5. This relationship directly links M
e with M
w via their common scaling to classical magnitudes and, at the same time, highlights the reason why M
w and M
e can significantly differ. In fact, Θ is assumed to be constant when calculating M
w. However, variations over three to four orders of magnitude in stress drop Δσ (as well as related variations in rupture velocity V
R and seismic wave radiation efficiency η
R) are responsible for the large variability of actual Θ values of earthquakes. As a result, for the same earthquake, M
e may sometimes differ by more than one magnitude unit from M
w. Such a difference is highly relevant when assessing the actual damage potential associated with a given earthquake, because
it expresses rather different static and dynamic source properties. While M
w is most appropriate for estimating the earthquake size (i.e., the product of rupture area times average displacement) and
thus the potential tsunami hazard posed by strong and great earthquakes in marine environs, M
e is more suitable than M
w for assessing the potential hazard of damage due to strong ground shaking, i.e., the earthquake strength. Therefore, whenever
possible, these two magnitudes should be both independently determined and jointly considered. Usually, only M
w is taken as a unified magnitude in many seismological applications (ShakeMap, seismic hazard studies, etc.) since procedures
to calculate it are well developed and accepted to be stable with small uncertainty. For many reasons, procedures for E
S and M
e calculation are affected by a larger uncertainty and are currently not yet available for all global earthquakes. Thus, despite
the physical importance of E
S in characterizing the seismic source, the use of M
e has been limited so far to the detriment of quicker and more complete rough estimates of both earthquake size and strength
and their causal relationships. Further studies are needed to improve E
S estimations in order to allow M
e to be extensively used as an important complement to M
w in common seismological practice and its applications. 相似文献
14.
Summary The lunar daily (L) and lunar monthly (M) variations in horizontal magnetic field (H), maximum electron density (N
max
), height of peak ionisation (h
max
), semi-thickness (y
m
) of theF
2 layer and total electron content (N
t
) at Huancayo for the period January 1960 to December 1961 are described. The lunar tidal variations inh
max
follow sympathetically the variations inH such that an increase of magnetic field causes the raising of height of peak ionisation. Lunar tides inN
max
are opposite in phase to that ofh
max
with a delay of about 1–2 hours, suggesting that an increase of height causes a decrease in maximum electron density. The lunar tides in semi-thickness are very similar in phase to that inh
max
. The lunar tidal effects in any of the parameters are largest inD-months and least inJ-months. The amplitude of lunar tides in maximum electron density seems to increase with increasing height whereas the phase seems to be constant with height. It is concluded that lunar tides in the ionospheric parameters at magnetic equator are greatly controlled by the corresponding geomagnetic variations.Presented at the Third International Symposium on Equatorial Aeronomy, Ahmedabad, 3–10 February 1969. 相似文献
15.
B. Tsegmed 《Geomagnetism and Aeronomy》2011,51(8):1138-1145
The spatio-temporal evolution of geomagnetic pulsation bursts at frequencies of 1–3 Hz, observed at the Mondy (MLT ≈ 1200;
Mlat = 46.8°; L = 2.16) and Borok (MLT ≈ 0820; Mlat = 54.0°; L = 2.94) midlatitude observatories and Lovozero auroral observatory (MLT ≈ 0820; Mlat = 64.2°; L = 5.36), has been studied. The considered bursts were registered in daytime sector of the magnetosphere after sudden impulses
(SIs) caused by dramatic increases in the solar wind dynamic pressure and registered on board the WIND satellite. The SI onset
time corresponds to the Sc* time shown in the Geomagnetic Indices Bulletin. The possible relationship between the excitation of these bursts and the variations in the particle partial density in the
range of energies 0.03–45 keV per unit charge has been studied. The bursts were registered on board the LANL geosynchronous
satellites. A comparison of the particle partial density variations measured on the satellites and the variation temperature
anisotropy (A = T⊥/T‖ − 1) with the variations in the pulsation burst amplitude on the ground indicated that the partial density maximum and the
minimum (A ≤ 0) of the electron temperature anisotropy index in the vicinity of local noon coincide in time with the pulsation generation
instant. A comparison of the electron partial density variations on the LANL-1994 and LANL-97A geosynchronous satellites spaced
in longitude and the spatio-temporal variations in the development of bursts make it possible to assume that 1–3 Hz geomagnetic
pulsations are excited in the vicinity of local noon and subsequently propagate along the ionospheric waveguide. 相似文献
16.
P. Stauning Oleg Troshichev Alexander Janzhura 《Journal of Atmospheric and Solar》2008,70(18):2246-2261
The polar geomagnetic activity resulting from solar wind–magnetosphere interactions can be characterized the Polar Cap (PC) indices, PCN and PCS. PC index values are derived from polar magnetic variations calibrated on a statistical basis such that the index approximate values in units of mV/m of the interplanetary “geo-effective” (or “merging”) electric field (EM) conveyed by the solar wind. The timing and amplitude relations of the PC index to solar wind plasma and magnetic field parameters are reported. The solar wind effects are parameterized in terms of the geo-effective electric field (EM) and the dynamical pressure (PDYN). The PC index has a delayed and damped response to EM variations and display saturation-like effects for EM values exceeding 10 mV/m. Steady or slowly varying levels of solar wind dynamical pressure have little or no impact on the PC index above the effects related to EM for which the solar wind velocity is also a factor. Sharp increases in the dynamical pressure generate impulsive variations in the PC index comprising a initial negative impulse of 5–10 min duration followed by a positive impulse lasting 10–20 min. Typical amplitudes of both the negative and the positive impulses are 0.2–0.5 units. A sharp decrease in the pressure produces the inverse sequence of pulses in the PC index. Auroral substorm activity represented by the AL index level has a marked influence on the average PC/EM level at the transition from very quiet (AL0 nT) to disturbed conditions while more or less disturbed conditions (AL<−100 nT) have no systematic effect on the average PC/EM values. At distinct substorm events the PC/EM ratio has a minimum (0.8) in the pre-onset phase at around 20 min before substorm onset. The average ratio gradually increases in the expansion phase to reach a maximum value (1.1) at around 40 min after substorm onset (or 20 min after the largest (negative) peak in AL). At substorm recovery during the next 2 h the PC/EM ratio decreases. Finally, we report on the application of polar magnetic variations to model the disturbance storm time (Dst) index development during magnetic storms by using the PC index as a source function to quantify the energy input to the ring current representing accumulated storm energy and characterized by the Dst index. 相似文献
17.
The effects of temperature, fO2 and composition on the electrical conductivity of silicate liquids have been experimentally determined from 1200 to 1550°C under a range of fO2 conditions sufficient to change the oxidation state of Fe from predominantly Fe2+ to Fe3+. Oxidation of ferrous to ferric iron in the melt has no measurable effect on the conductivity of melts with relatively low ratios of divalent to univalent cations. Under strongly oxidizing conditions a minor decrease of conductivity is detected inth highΣM2/ΣM+ ratios. It is concluded that for purposes of estimating the conductivity of magmatic liquids, fO2 may be ignored to a first approximation. Both univalent and divalent cation transport is involved in electrical conduction. Melts relying heavily on divalent cations for conduction, i.e. melts with relatively large ΣM2+/ΣM+ ratios, show strong departures from Arrheenius temperature dependence with the apparent activation energies decreasing steadily as the temperature increases. Conductivities dominated by the univalent cations, in melts with relatively small ΣM2+/ΣM+ ratios, show classical Arrhenius temperature dependence. These observations are discussed in terms of the general characteristics of the melt structure.Compositional variations within the magmatic range account for much less than an order of magnitude variation in electrical conductivity at a fixed temperature. This observation, combined with previous measurements of the conductivity of olivine (A. Duba, H.C. Heard and R. Schock, 1974) make it possible to state with reasonable confidence that melts occurring within the mantle will be more conductive by 3–4 orders of magnitude than their refractory residues. Potential applications to geothermometry are discussed. 相似文献
18.
G. A. Popandopoulos 《Izvestiya Physics of the Solid Earth》2018,54(4):612-631
The time variations in the Gutenberg–Richter b-value are minutely studied based on the data of highly accurate seismological observations at the Garm prognostic site, Tajikistan, where a stationary network of seismic stations of the Complex Seismological Expedition (CSE) of Schmidt Institute of Physics of the Earth (IPE) of the USSR (Russian) Academy of Sciences was in operation from 1955 to 1992. A total of 93035 local earthquakes ranging from 0.0 to 6.3 in the Ml magnitudes are considered. The spatiotemporal fluctuations in the minimal magnitude of completeness of the earthquakes, Mc, are analyzed. The study considers a 25-year interval of the observations at the center of the observation system within which Mc = 0.9. It is shown that in most cases, the b-value and log10E2/3 experience characteristic time variations before the earthquakes with magnitudes higher than the minimal magnitude of the predicted earthquake (MPE). The 6-year anomaly in the parameters’ b-value, log10E2/3, and log10N associated with the single strongest earthquake with M = 6.3 that occurred in the observation region on October 26, 1984 is revealed. The inversely proportional relationship is established between the time variations in the b-value and the time variations in the velocities of seismic waves Vp and Vp/Vs. It is shown that the exponent p in the power function which links the time variations of the b-value and log10E2/3 is higher in the zones of crustal compression than in the zones of extension. It is simultaneously confirmed that the average b-value in the zones of compression is lower than in the zones of extension. It is established that in the case of earthquakes with M ≥ 2.6, the time series of seismic activity log10Ni and the time series of the b-value are highly cross correlated with a coefficient of r ≈ 0.75, whereas in the case of earthquakes with M ≥ 0.9, the coefficient of cross correlation between these time series is close to zero (r ≈ 0.06). The law of variations in the slope of the lines approximating the relationship between the log10Ni time series in the different magnitude ranges (M ≥ Mci) and b-value time series is obtained. It is hypothesized that the seismic activity of the earthquakes with high magnitudes can be estimated provided that the parameters of the time series of the b-value and time series of the number of earthquakes logN(ΔMi) in the range of low magnitudes are known. It is concluded that using the parameter log10N for prognostic estimates of the strong earthquakes only makes sense for earthquakes having moderate and large magnitudes. It is inferred that the time variations in the b-value are predominantly contributed by the time variations of the earthquakes with relatively large magnitudes. 相似文献
19.
Three-dimensional velocity structure around the focal area of the 2021 MS6.4 Yangbi earthquake 
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下载免费PDF全文 Yunpeng Zhang Weitao Wang Wei Yang Min Liu Jinbo Su Xiaobin Li Jun Yang 《地震科学（英文版）》2021,34(5):399-412
On May 21, 2021, an MS6.4 earthquake occurred in Yangbi, Yunnan province, China, which exhibited typical foreshock-mainshock-aftershock characteristics. To better understand the velocity structure of the focal area and adjacent fault zones, Pg/Sg travel times at 12 seismic stations for the local earthquakes with ML ≥ 1.5 from 2009–2019 and the Yangbi sequence in May of 2021 were used to invert the three-dimensional (3D) structures for both vP and vP/vS. The obtained structure extends deeply to 15 km for area (25°N–26.5°N, 99.5°E–101°E) at a horizontal resolution of 10× 10 km, and the accuracy of the vP velocity was verified using airgun signals excited by the Binchuan Airgun Transmitting Seismic Station (BATSS). The resulting vP and vP/vS images correlate with existing fault zones and the Yangbi sequence, including: (1) The shallow velocity structure at 0 km agrees with local topography, where the Binchuan basin exhibits low-vP and high-vP/vS values. From 3–15 km, vP and vP/vS show variations, and the boundaries are consistent with the main faults (e.g., the Weixi-Qiaohou-Weishan, Honghe, and Chenghai faults). (2) The largest foreshock (MS5.6), mainshock (MS6.4), and largest aftershock (MS5.2) occurred near the boundaries where both vP and vP/vS have clear contrasts. (3) Small earthquakes are also concentrated in the transition zone between high- and low-vP and vP/vS anomalies, and are biased toward low-vP/vS zones. (4) Boundaries in vP and vP/vS are observed at 20 km west of the Weixi-Qiaohou-Weishan fault, indicating that there may exist one hidden fault. 相似文献
20.
Katsuyuki Abe 《Physics of the Earth and Planetary Interiors》1985,38(4):214-223
The size of major tsunamigenic earthquakes which occurred in the Japan Sea is quantified on the basis of seismic and tsunamigenic source parameters. The tsunami magnitude Mt is determined from the instrumental tsunami-wave amplitudes. The Mt values thus obtained are on average 0.2 units larger than the values of moment magnitude Mw, though the Mt scale has originally been adjusted to agree with Mw. Moreover, the volume of displaced water at the source is on average 2.3 times as large as that for the Pacific events with a comparable Mw. Nevertheless, the observed height of the sea-level disturbance at the source is found consistent with the amount of crustal deformation computed for the seismic fault models. These results indicate that the tsunami source potential itself is large for Mw in comparison with the Pacific events. The large source potential is explained in terms of the effective difference both in the rigidity of the source medium and in the geometry of the fault motion. For the Japan Sea events, the Mt scale still provides the physical measure of the tsunami potential, and Mt minus 0.2 corresponds to Mw. This predicts that the maximum amplitude of tsunami waves from Japan Sea earthquakes is at least two times as large as that from Pacific earthquakes with a comparable Mw. 相似文献