Tag Archives: seismology

Quakes by InSight indicate Mars’ interior is active

Cerberus Fossae

The first seismic results from InSight’s seismometer now show that the interior of Mars is active, with regular moderately-sized quakes.

The Seismic Experiment for Interior Structure (SEIS) instrument – a seismometer developed by an international consortium under the leadership of the French space agency CNES – recorded a total of 174 seismic events between February and September 2019. Twenty of these marsquakes had a magnitude of between three and four. Quakes of this intensity correspond to weak seismic activity of the kind that occurs repeatedly on Earth in the middle of continental plates, for example in Germany on the southern edge of the Swabian Jura hills.

Although only one measurement station is available, models of wave propagation in the Martian soil have been used to determine the probable source of two of these quakes. It is located in the Cerberus Fossae region, a young volcanic area approximately 1700 kilometres east of the landing site.

Cerberus Fossae is a land of cracks and linear depressions located between the giant volcanoes, Elysium Mons to the north and Olympus Mons to the east. It is believed those fissures were caused by the rise of those volcanoes, stretching the crust and cracking it.

This new data from InSight strengthens this theory.

Mapping the inside of Mt St. Helens

A new array of seismometers, combined with a series of planned explosions, will be used to map the interior of the Mt. St. Helens volcano to a depth of eighty kilometers or fifty miles.

To get the job done, starting next week roughly 65 people will fan out across the mountain to deploy 3,500 small seismometers along roads and back-country trails. They will drill 24 holes some 25 metres deep, drop in industrial explosives used for quarrying, and refill the holes (see ‘Under the dome’). The plan is to detonate the explosives in separate shots over four nights. Each blast will shake the ground as much as a magnitude-2 earthquake.

Results from the active blasts will be combined with the passive seismic part of the experiment, which is already under way: 70 larger seis­mometers around the mountain are measuring how long waves from natural earthquakes take to travel through the ground. Their data can be used to probe as far as 80 kilo­metres down, says Vidale.

The manslaughter trial of six scientists and one government official continued yesterday in Italy over their reassurances to the public prior to a deadly earthquake in 2009.

The manslaughter trial of six scientists and one government official continued yesterday in Italy over their reassurances to the public prior to a deadly earthquake in 2009.

Guido Bertolaso, former head of the Department of Civil Protection and De Bernardinis’s direct superior, had not been indicted and was originally expected to appear as a witness. But a few weeks ago a wiretap revealed that he had apparently set up the meeting to convey a reassuring message, regardless of the scientists’ opinion. He also seemed to be the source of the “discharge of energy” statement. He thus found himself under investigation and, at the beginning of the hearing, he was officially notified that he too may soon be formally indicted for manslaughter.

Bertolaso was asked by the prosecutor to explain that telephone conversation. He defended himself by saying that by defining the meeting as a “media move”, he was not trying to downplay risks but rather to put some order into the contradictory information that was reaching the citizens in those days. In particular, he referred to Giampaolo Giuliani — a laboratory technician and amateur seismologist who was alarming the population with claims that a major shock was coming — and to a newspaper article that had misquoted some Civil Protection experts and stated that the shocks would soon be over. The meeting, he said, was meant to make clear that both were wrong and that no deterministic prediction could be made. [emphasis mine]

This increasingly appears to be another case of science being corrupted by politics.