Abstract：
Electromagnetic emissions from earthquakes are known as precursors and are of considerable importance for the purpose of early alarms. The propagation of low-frequency waves is favored, and the range between tens of mHz to tens of Hz has been heavily investigated in the last thirty years. This work describes the self-financed Opera 2015 project that initially consisted of six monitoring stations over Italy, equipped with electric and magnetic field sensors, among others. Insight of the designed antennas and low-noise electronic amplifiers provides both characterization of performance (similar to the best commercial products) and the elements to replicate the design for our own independent studies. Measured signals through data acquisition systems were then processed for spectral analysis and are available on the Opera 2015 website. Data provided by other world-known research institutes have also been considered for comparison. The work provides examples of processing methods and results representation, identifying many exogenous noise contributions of natural or human-made origin. The study of the results occurred for some years and led us to think that reliable precursors are confined to a short area around the earthquake due to the significant attenuation and the effect of overlapping noise sources. To this aim, a magnitude-distance indicator was developed to classify the detectability of the EQ events observed during 2015 and compared this with some other known earthquake events documented in the scientific literature.
摘要：
地震的电磁辐射被称为前兆，对于早期警报的目的非常重要。低频波的传播受到青睐,在过去的三十年中，人们对几十mHz到几十Hz之间的范围进行了大量研究。这项工作描述了自筹资金的Opera2015项目，该项目最初由意大利的六个监测站组成，配有电场和磁场传感器，在其他人中。对设计的天线和低噪声电子放大器的洞察提供了性能表征（类似于最佳商业产品）和为我们自己的独立研究复制设计的元素。然后通过数据采集系统测量的信号进行频谱分析，并在Opera2015网站上提供。其他世界知名研究机构提供的数据也被考虑进行比较。该工作提供了处理方法和结果表示的示例，识别自然或人为起源的许多外源噪声贡献。对结果的研究发生了几年，使我们认为，由于显着的衰减和重叠的噪声源的影响，可靠的前兆仅限于地震周围的较短区域。为了这个目标,我们开发了震级-距离指标来对2015年期间观测到的EQ事件的可检测性进行分类,并将其与科学文献中记录的其他一些已知地震事件进行了比较.
