As earthquakes occur without warning, it helps to know in advance what you should do if one does happen. The standard recommendation in Switzerland and elsewhere is: seek cover. That might be under a sturdy table or by holding a pillow over your head in bed. Many earthquake injuries are caused by falling objects such as shelf contents or ceiling or wall materials. If you run around in a panic during the quake, you are more likely to be hit by such objects. What's more, even keeping your balance can be difficult during a powerful earthquake, so you'll probably want to cling on to something that offers protection (the Director of the Seismological Service found this out for himself, as you can see in the next episode of Einstein to be broadcast on SRF).

However, as so often, there are exceptions to this rule. If you're near the sea, running inland is a better option due to the possibility of a subsequent tsunami. In Alaska, they have the following rule of thumb: if the quake is strong enough to almost knock you over, run up the nearest hill. Likewise, if you are indoors but very close to an exit, head outside. If you're already outside, stay there and keep away from buildings. Detailed recommendations on what to do can be found here. Essentially, the right action to take during an earthquake very much depends on the circumstances (the type of earthquake, the type of building, where you are, and so on).

This makes it difficult for seismologists to give general recommendations without causing undue anxiety. The most important protection against earthquakes is and will always be appropriate construction. However, judging how earthquake-resistant a building is just by looking at it is hard even for experts, so this is probably not something that you can take into account when choosing accommodation. That said, it's often the case that the newer a building is, the more likely it is to comply with the latest building standards and therefore to be earthquake-resistant. 

Once the tremors are over, heavily damaged buildings should be evacuated. While making your way outside, beware of falling objects such as bricks and tiles or disconnected power lines. Aftershocks, some of them strong, are likely to occur after a major quake, and these may cause further damage. In genaral, always follow the instructions of the local authorities.

Should you wish to take further precautions, this page lists recommendations for things you can do ahead of shorter or longer trips. All the information can also be downloaded as a fact sheet.

Last but not least, don't forget that, while earthquakes are real, the risk of being harmed by one is extremely small, even in seismically active areas. For example, if you're travelling to California, the risk is 1 in 1,000,0000 per year. Driving a car there is much more dangerous, with around a 1 in 11,428 chance of being involved in a serious accident. So the message is: make a few simple preparations and then enjoy your well-deserved holidays!

Am Mittwoch, dem 16. Mai 2018, hat sich um 11:32 Uhr ein zweites Beben ereignet. Die Magnitude war mit 2.9 leicht schwächer. Das Epizentrum dieses Bebens liegt am selben Ort wie jenes des ersten (etwas 2 km südwestlich von Châtel-St-Denis). Das zweite Beben ereignete sich aber vermutlich noch ein bisschen näher an der Erdoberfläche.

The InSight Lander will place a seismometer, dubbed SEIS (standing for Seismic Experiment for Interior Structure), on the surface of Mars. As soon as data gathered by SEIS arrive at ETH Zurich, seismologists from the Swiss Seismological Service (SED) and the Seismology and Geodynamics Group (SEG) will analyse them as part of their routine work. However, with just one seismometer in place, this will be no easy task. Unlike on Earth, where seismologists can rely on very many recording stations to precisely determine the origin of a tremor, on Mars there will be no addtional reference points. For this reason, special care will be taken to extract as much information as possible from even the weakest signals indicating possible marsquakes, meteorite impacts or even minor tornadoes. For this purpose, staff at the Marsquake Service will combine methods taken from the early days of seismology, when there were only a few seismometers on Earth, with modern analytic methods for locating seismic events.

It is hoped that the results of the InSight mission will provide insights into one of the fundamental questions of planetary and solar system research, giving us a better understanding of the processes that created the Earth-like planets of the inner solar system (including Earth) more than 4 billion years ago. 

Learn more about the InSight mission and related acitivites at ETH www.insight.ethz.ch

See what our Mars scientists are telling about the @NASAInSight mission

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Seismograms of induced earthquakes are generally indistinguishable from those of natural earthquakes. Therefore, investigations focus on a range of indicators, taking into account the location of earthquakes, their depths, and the history of stimulation activities conducted underground. By analyzing publically available continuous waveform and geodetic data from satellites, the paper contributes to the understanding of the nature of the event.

The study shows that the mainshock and its largest aftershocks occurred within 2 km distance or less of the geothermal site. Furthermore, they are located within 1.5 km distance of an induced event, which occurred in April 2017 during one of the underground stimulation operations. These locations are confirmed by a Korean study, which has been simultaneously published in Science. In general, the closer an earthquake sequence is located to a geothermal site and to previous related seismic activity, as well as the sooner it happens after underground operations, the greater the chance of being related to it. The mainshock and the 46 aftershocks detected between 15 and 30 November 2017 all occurred at depths of 3 to 7 kilometres. Such depths are unusually shallow when compared to previously registered natural events in the area. The analysis of satellite data illustrates that the mainshock displaced the surface of the earth permanently by up to 4 cm, indicating that the activated, and previously unknown fault, is a steeply dipping and very shallow thrust fault that passes directly beneath the bottom hole section.

These indications combined lead to the conclusion that a connection between the magnitude 5.5 earthquake in South Korea and the nearby geothermal project is plausible. However, the mainshock occurred about two months after the last stimulation activities. So far, there is no quantitative model available that relates the injection activities conducted to the occurrence of this event. The Korean government has appointed an independent expert commission to examine all pieces of evidence and to evaluate if the event was triggered or induced by the nearby stimulation activities. To our understanding, the commission will (re-)analyze all available data and models, including microseismicity data, injection volumes, reservoir pressures, and detailed hydrological and geological data, which are essential to understand the relation between the injection operations and the earthquake sequence.

The Swiss Seismological Service (SED) at ETH Zurich has first informed the public (see SED news) in November 2017 about the Pohang earthquake in the context of the release of a good practice report on induced seismicity. At the same time, Geo-Energie Suisse AG had notified the canton of Jura, where currently the only EGS-style deep geothermal project in Switzerland has applied for a construction permit. In consequence, the canton instructed Geo-Energie Suisse AG to evaluate potential implications for the planned Haute-Sorne geothermal project. An immerged understanding of the link between the magnitude 5.5 Pohang earthquake and the nearby geothermal project is crucial for a safe and sustainable future exploitation of geothermal energy.