China launches satellite to study earthquake precursors

China today successfully launched its first seismo-electromagnetic satellite to study seismic precursors, which might help it establish a ground-space earthquake monitoring and forecasting network in the future.
A Long March-2D rocket, which was launched from Jiuquan Satellite Launch Centre in northwest China's Gobi Desert at 15:51 (local times), carried the 730-kilogramme China Seismo- Electromagnetic Satellite (CSES) into a sun-synchronous orbit at an altitude of about 500 Kms, the state-run Xinhua news agency reported.
Known as Zhangheng 1 in Chinese, it will help scientists monitor the electromagnetic field, ionospheric plasma and high-energy particles for an expected mission life of five years, Zhao Jian, a senior official with China National Space Administration (CNSA) said.

The satellite is named after Zhang Heng, a scholar of the East Han Dynasty (25-220), who pioneered earthquake studies by inventing the first ever seismoscope in the year 132.
Zhangheng 1 will record electromagnetic data associated with earthquakes above 6 magnitude in China and those above 7 magnitude around the world, in a bid to identify patterns in the electromagnetic disturbances in the near-Earth environment, Zhao said.
It will focus on Chinese mainland, areas within 1,000 kms to China's land borders and two major global earthquake belts.

The satellite will help scientists understand better the coupling mechanisms of the upper atmosphere, ionosphere and magnetosphere and the temporal variations of the geomagnetic field, and thus accumulate data for the research of seismic precursors, Zhao said.

"Zhangheng 1 cannot be used to predict earthquakes directly, but it will help prepare the research and technologies for a ground-space earthquake monitoring and forecasting system in the future," he said.
A senior manager with DFH Satellite Company Zhou Feng said that Zhangheng 1 is a cubic satellite, 1.4 meters on each side. It has a single solar panel and six booms, which will deploy and keep electromagnetic detectors more than 4 meters away from the satellite.
It carries a high-precision magnetometer, a search-coil magnetometer and electric field probes to measure components and intensity of the magnetic and electric fields. It is also equipped with a Langmuir probe, a plasma analyzer, a GNSS occultation receiver and a tri-band beacon to measure in-situ plasma and ionospheric profile as well, Zhou said.

It also carries high-energy particle detectors, some of which are provided by Italian partners, and a magnetic field calibration device developed in Austria, according to Zhou.
Research shows that just before a quake, tectonic forces acting on the Earth's crust emit electromagnetic waves and twist magnetic field lines. But such electromagnetic phenomena are relatively weak and need further study to be useful.