震源

Plane wave: Having wavefronts which are planar, as might originate from a very remote source.

平面波：波阵面是平面的波，如震源很远的波。

The result shows that the Haiyuan fault is an overlap fold-fault taking the shape of the shovel with depth less than 10 km,which bears no relation to occurrence of the 1920 Haiyuan earthquake because the focal depth of the earthquake is 15～20 km.

结果表明：海原断层实际是深度不超过10km的铲状逆掩推覆断层，而海原大震的震源深度为15～20km，因此，海原断层与该次大震的发生无关。

The analyzing aboved is made from earthquake's space distributing, periodicity, migration phenomenon, repetition, strength, frequency, b value etc., according to data of earthquake station net in Shaanxi Province and microseisms station net watching results in Xi'an area. 3 group faults which are NEE, NW and EW direction control earthquake activities in Guanzhong area. Epicenter depth mostly is 5-25km and in shallow-focus earthquake. Earthquake in east area of Guanzhong was stronger and weaker in the West in history. Fen-Wei earthquake belt showed more activity. Microseisms and small seisms is main movement in recent earthquake, it has 8-10years' period of movement and show the trend that they are strong in the West but weaker in the East. And frequency and biggest magnitude of earthquake is supplement each other. In next years earthquake frequency will lessen but strength enhance, about M4. It presumes there is earthquake climax period in Guanzhong area in 2040 and M5-6 earthquake is happened at that time.

本文在对关中地区区域构造及重磁异常特征的分析基础上，根据陕西省地震台网监测资料及西安地区微地震台网监测成果，从地震的空间分布特征、周期性、迁移现象、重复性、强度、频度、b值分析等方面，对区域地震活动特征、关中地区地震活动规律进行了分析研究，关中地区地震活动主要受北东—北东东向、北西向、东西向三组方向的断裂控制，震源深度多为5—25公里，均属浅源地震，历史地震表现为东强西弱，东部的汾渭地震带表现出较强的地震活动性，近代地震活动主要以微震或小震为主，存在着8—10年的活动周期，近期表现出西强东弱的趋势，地震的频度与地震最大震级呈互补关系，未来的几年间，地震频度会有所减少，强度会增大，将有可能发生4级左右的地震，推测在2040年左右，关中地区将进入地震高潮期，届时将可能有5—6级左右的地震发生。

We suggest a method abandoning the search for common converted points and adjusting polars, and taking receive point as fictitious source, and using one-way wave equation performance to converted wave migration in shot domain.

抛开常规的转换点位置估计及极性校正，把检波点作为虚拟震源，利用单程波方程实现转换波记录的炮域偏移处理。

In this paper, on the basis of geologic model, the propagation model of Rayleigh wave is deduced, which is caused by vibration point source and propagates in multi-layer of media.

该文根据地质模型假设，推导出多层介质条件下由点震源的作用在介质中引起的瑞雷波的传播模型，并用此模型对不同目标运动时所产生的瑞雷波信号加以预测。

Assumption of plane waves radiating from a point source leads to two rotational components: rocking around a horizontal axis perpendicular to the source-site direction and torsion around a vertical axis.

点源面波辐射假设产生了两个旋转分量：绕水平轴垂直于震源-场地方向的摇摆及绕垂直轴的扭转。

The Sichuan earthquake of May 12, 2008, occurred as the result of motion on a northeast striking reverse fault or thrust fault on the northwestern margin of the Sichuan Basin.

本次地震是东北向运动的断层碰撞四川盆地西北部而成，地震震中与震源机制皆与龙门山以其相连断层的运动吻合。

Theories and method of fracture detection by down- going S-wave information from zero offset three-component VSP data were introduced.

介绍了利用纵波震源零井源距三分量VSP资料的下行横波信息对井旁裂缝进行检测的原理和实现方法。

Hammer: A hammer striking a steel plate is used as seismic source for shallow refraction measurements.

冲击锤：浅层折射法中用于锤击钢板来作为震源的锤。

From the mechani sms the NNE Tianwan fault is of left lateral strike slip with the pressure from NW direction.

由震源机制解得知，北北东走向的田湾断层是承受着北西方向压应力的左旋走滑型逆断层。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。