At approximately 09:25:17 UTC on Friday, March 23rd, a 5.6 magnitude earthquake based on land struck at a depth of 10.7 km (6.6 miles) in the region of the South Australia, 217 km (196 miles) SSW of Alice Springs, Australia. Coords: 10.387°S, 161.262°E … (USGS)
According to Geoscience Australia, the initial arrival was from 09:25:44 – 09:29:14 (UTC).
Geoscience has the depth at 3 km at present. Australia itself does not run over any prominent fault lines, so earthquakes further inland, like this one, are a rarity, though not unheard of.
The epicentre itself was 370 kilometres west-north-west of Oodnadatta, near the Northern Territory-South Australian border.
A lot happened while we were down. Sunspot 1402 decided to show its strength as it crossed over the visible corona. From the start it began shooting out M class flares, and just as it was leaving it did the same. The strongest flare it released was an X5 class flare, which produced a large CME that mostly hit Earth. On top of several other C and M class flares, the magnetic field has had to work over time on certain occasions as of late.
The volcanic situation is interesting as always, with a few new candidates appearing on the scene, with a few old timers like Etna continuing on and on.
The largest earthquake we’ve seen since we’ve been gone was a 7.4 magnitude quake that struck Mexico on the 20th, following a 6.9 that struck Japan just a few days earlier, and prior to a 6.6 that struck PNG late on the 21st. The 188 day theory did not hold true, unfortunately. The idea was that there was a megaquake separated by a 7 mag quake in this pattern, since February 27, 2010. While we did have some 6 magnitude action and a 7.4, it still isn’t enough to say that this cycle held out. I think that it may be indicative of a pattern of movement roughly every 6 months or so, but rounding it down to the day, or hour, is likely to yield no real results. That’s all at present. The equinox has come, and now shall the colours of 2012 really start to come through.
(Activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)
A lava lake present within the Halema’uma’u Overlook vent during the past week resulted in night-time glow that was visible from the Jaggar Museum overlook. The lake, which is normally about 90–115 m (295–377 ft) below the floor of Halema’uma’u Crater and visible by HVO`s Webcam, rose and fell slightly during the week in response to a series of large deflation-inflation cycles.
On Kilauea’s east rift zone, surface lava flows were active on the pali and upper coastal plain, in Royal Gardens subdivision, over the past week. As of Thursday, March 22, the flows were still more than 2 km (1.2 miles) from the coast, and there was no active ocean entry.
Two earthquakes beneath Hawai’i Island were reported felt this past week. A magnitude-2.7 earthquake occurred at 3:42 p.m., HST, on Monday, March 19, 2012, and was located 4 km (2 mi) southeast of Pu’ulena Crater at a depth of 2 km (1 mi). A magnitude-3.7 earthquake occurred at 00:04 a.m. (4 minutes after midnight) on Thursday, March 22, and was located 40 km (25 mi) west and offshore of Kailua-Kona at a depth of 33 km (21 miles).
A minor earthquake occurred this week near the eastern Wisconsin city where researchers have been investigating a series of unexplained booming sounds, federal geologists said Thursday.
The U.S. Geological Survey said the 1.5-magnitude earthquake struck Tuesday just after midnight in Clintonville, a town of about 4,600 people about 40 miles west of Green Bay.
Geophysicist Paul Caruso told The Associated Press that loud booming noises have been known to accompany earthquakes. It’s possible the mysterious sounds that town officials have been investigating are linked to the quake, he said.
Earthquakes can generate seismic energy that moves through rock at thousands of miles per hour, producing a sonic boom when the waves come to the surface, Caruso said.
“To be honest, I’m skeptical that there’d be a sound report associated with such a small earthquake, but it’s possible,” he said.
Those reservations didn’t stop Clintonville City Administrator Lisa Kuss from declaring “the mystery is solved” at a news conference Thursday evening.
She said USGS representatives described the event as a swarm of several small earthquakes in a very short time.
“In other places in the United States, a 1.5 earthquake would not be felt,” she said. “But the type of rock Wisconsin has transmits seismic energy very well.”
The U.S. Geological Survey says earthquakes with magnitude of 2.0 or less aren’t commonly felt by people and are generally recorded only on local seismographs. Caruso said the Tuesday earthquake was discovered after people reported feeling something, and geologists pored through their data to determine that an earthquake did indeed strike.
Local residents have reported late-night disturbances since Sunday, including a shaking ground and loud booms that sound like thunder or fireworks.
City officials investigated and ruled out a number of human-related explanations, such as construction, traffic, military exercises and underground work.
Clintonville resident Jordan Pfeiler, 21, said she doubted an earthquake caused the noises. She said the booms she experienced were in a series over the course of several hours and not continuous as she might have expected if they were caused by an earthquake.
Still, she said, “It’s a little scary knowing Clintonville could even have earthquakes.”
Steve Dutch, a geologist at the University of Wisconsin-Green Bay, said a 1.5 magnitude earthquake produces the energy equivalent of 100 pounds of explosives and could produce loud sounds.
Authorities today ruled El Salvador declare an emergency for low-magnitude earthquakes that have shaken the Salvadoran capital, all centered in the San Salvador volcano, eight of them felt by the population and the strongest of 3.3 degrees on the Richter scale.
“There is no evidence that we are facing a potential emergency,” said Minister of Environment and Natural Resources, Herman Rosa Chavez, in a press conference in which he reiterated that no volcanic tremor, but tectonic.
“We did analysis of temperature in the area and there is no evidence that this is associated with volcanic activity, this has to do with the activation of local faults, which is something that happens and has happened before,” he said.
The eight tremors felt by the population have reached levels of between 2.2 and 3.3 degrees on the Richter scale, according to the National Service of Territorial Studies (SNET), which has recorded at least 25 microearthquakes.
The first quake was felt that reached 2.6 degrees and was registered at 01.22 local time (7.22 GMT), and most recently, of 2.7 degrees, at 15.50 (21.50 GMT).
The strongest earthquake of 3.3 degrees, occurred at 08.01 (14.01 GMT), said the SNET.
He added that the focal depth of earthquakes has fluctuated between 0.5 and 5.8 kilometers, so they felt in various parts of the city, near which is the San Salvador volcano, which is inactive.
Likewise, the eight earthquakes have reached an intensity of two on the Mercalli scale, whose maximum is 12, in San Salvador.
The Ministry of Environment and Natural Resources in a statement recalled that the last seismic swarm with epicenter in the San Salvador volcano was in 2007 when there were 142 microearthquakes, four of them felt by the population.
Apart from the string of earthquakes in San Salvador, today reported another quake Snet of 4.3 on the Richter scale at 11.26 local time (17.26 GMT) in Pacific Ocean, about 43 kilometers south of the estuary San Diego, in the department of La Libertad (center).
“After decades of little activity, a series of earthquakes and deformation began within the Santorini caldera in January of 2011,” said Newman, whose research is published by Geophysical Research Letters. “Since then, our instruments on the northern part of the island have moved laterally between five and nine centimeters. The volcano’s magma chamber is filling, and we are keeping a close eye on its activity.”
Newman, a geophysicist in the School of Earth and Atmospheric Sciences, cannot be certain whether an eruption is imminent since observations of such activity on these types of volcanoes are limited. In fact, similar calderas around the globe have shown comparable activity without erupting. However, Newman says the chamber has expanded by 14 million cubic meters since last January. That means enough magma has been pumped into the chamber to fill a sphere three football fields across.
Should Santorini erupt, Newman says it will likely be comparable to what the island has seen in the last 450 years.
“That could be dangerous,” notes Newman. “If the caldera erupts underwater, it could cause local tsunamis and affect boat traffic, including cruise ships, in the caldera. Earthquakes could damage homes and produce landslides along the cliffs.”
More than 50,000 tourists a day flock to Santorini in the summer months (from May to October). It’s common to see as many as five cruise ships floating above the volcano.
Santorini is the site of one of the largest volcanic events in human history. The Minoan eruption, which occurred around 1650 B.C., buried the major port city of Akrotiri with more than 20 meters of ash and created Santorini’s famous, present-day cliffs. Newman says such history will likely not repeat itself any time soon. Such an eruption comes along once every 100,000 years, and the current inflation in the magma chamber is less than 1 percent of the Minoan blast.
Stony Brook University researchers have devised a numerical model to help explain the linkage between earthquakes and the powerful forces that cause them, according to a research paper scheduled to be published in the journal Science on Feb. 17. Their findings hold implications for long-term forecasting of earthquakes.
William E. Holt, Ph.D., a professor in the Geosciences Department at Stony Brook University, and Attreyee Ghosh, Ph.D., a post doctoral associate, used their model to help explain the stresses that act on Earth’s tectonic plates. Those stresses result in earthquakes not only at the boundaries between tectonic plates, where most earthquakes occur, but also in the plate interiors, where the forces are less understood, according to their paper, “Plate Motions and Stresses from Global Dynamic Models.”
“If you take into account the effects of topography and all density variations within the plates — the Earth’s crust varies in thickness depending on where you are — if you take all that into account, together with the mantle convection system, you can do a good job explaining what is going on at the surface,” said Dr. Holt.
Their research focused on the system of plates that float on Earth’s fluid-like mantle, which acts as a convection system on geologic time scales, carrying them and the continents that rest upon them. These plates bump and grind past one another, diverge from one another, or collide or sink (subduct) along the plate boundary zones of the world. Collisions between the continents have produced spectacular mountain ranges and powerful earthquakes. But the constant stress to which the plates are subjected also results in earthquakes within the interior of those plates.
“Predicting plate motions correctly, along with stresses within the plates, has been a challenge for global dynamic models,” the researchers wrote. “Accurate predictions of these is vitally important for understanding the forces responsible for the movement of plates, mountain building, rifting of continents, and strain accumulation released in earthquakes.”
Data for their global computer model came from Global Positioning System (GPS) measurements, which track the movements of Earth’s crust within the deforming plate boundary zones; measurements on the orientation of Earth’s stress field gleaned from earthquake faults; and a network of global seismometers that provided a picture of Earth’s interior density variations. They compared output from their model with these measurements from Earth’s surface.
“These observations — GPS, faults — allow one to test the completeness of the model,” Dr. Holt said.
Drs. Ghosh and Holt found that plate tectonics is an integrated system, driven by density variations found between the surface of Earth all the way to Earth’s core-mantle boundary. A surprising find was the variation in influence between relatively shallow features (topography and crustal thickness variations) and deeper large-scale mantle flow patterns that assist and, in some places, resist plate motions. Ghosh and Holt also found that it is the large-scale mantle flow patterns, set up by the long history of sinking plates, that are important for influencing the stresses within, and motions of, the plates.
Topography also has a major influence on the plate tectonic system, the researchers found. That result suggests a powerful feedback between the forces that make the topography and the ‘push-back’ on the system exerted by the topography, they explained.
While their model cannot accurately predict when and where earthquakes will occur in the short-term, “it can help at better understanding or forecasting earthquakes over longer time spans,” Dr. Holt said. “Nobody can yet predict, but ultimately given a better understanding of the forces within the system, one can develop better forecast models.”
Riyadh: A heavy sandstorm hit the Saudi capital yesterday, making the city totally dark after 4 p.m. as it swept through neighboring areas.
“Darkness enveloped the main arteries of the capital city such as Qassim, King Fahd, Khurais and Makkah roads because of the storm which started at about 12 noon,” said Benny M. Quiambao, a Filipino building contractor. Drivers slowed down and switched on their hazard lights as visibility dropped to zero, he said.
Earlier, the Presidency of Meteorology and Environment (PME) had warned that a sandstorm was approaching Riyadh with a one-meter horizontal visibility.
Director General of Health Affairs in Riyadh Dr. Adnan bin Sulaiman Al-Abdulkarim, announced at 3 p.m. yesterday that hospitals under the Ministry of Health were ready to admit dust-hit patients.
Other regions like Qassim and Hail had also been affected. “The sandstorm started at 8:30 in the morning in Qassim, followed by rains at about 12:15 in the afternoon. It stopped at about 3:30 p.m.,” said Arnold G. Pineda, a community leader in Buraidah. He added that by 5:30 p.m. the rains had stopped but the skies remained cloudy.
Edmund Nieto, who works for the STC in Hail, said there was no storm in the area. “However, there were intermittent rains and the skies were cloudy the whole day,” he said.
Murad Al-Sagaf, manufacturing director at a Saudi firm in Buraidah, added that in the northern region, it was cloudy with intermittent rains.
The earth shook in Crévoux, 16 km northeast of Barceloneta, tonight at 11:37 p.m. accurate, according to the website of Atomic Energy Commission (CEA).
The earthquake measuring 4.9 on the Richter scale was felt in the Var, Alpes-Maritimes and even Marseille where many people have felt the tremor for 3 to 4 seconds.
Not since 1997 to find an equivalent amplitude in this mountainous region of the Hautes-Alpes.
A shallow 5.9-magnitude earthquake sent people fleeing onto the streets in Taiwan’s second-largest city of Kaohsiung and led to temporary halting of rail services. No casualties were reported yesterday.
The quake struck 57 kilometers east of the southern city at 10.34am at a depth of just four kilometers, the US Geological Survey said. The Hong Kong Observatory measured the quake at a magnitude of six, while Taiwan’s Seismology Centre put it at 6.1. The National Fire Agency said there were no casualties or major material damage.
“A few Kaohsiung residents sought safety in the streets for a short while, but it wasn’t many,” a police officer said.
A spokesman for the center said it is relatively rare for a quake of such magnitude to hit the Kaohsiung area. “While the quake was strong, it didn’t last long,” Chen Jung-yu said.
“Even in some towns near the epicenter, buildings swayed for no more than seven seconds. That explained why it did not inflict damages.”
A high-speed railway linking Kaohsiung with Taipei in the north resumed about 90 minutes after the quake prompted services to be suspended. The greater metropolitan area of Kaohsiung has a population of nearly three million.
Taiwan is regularly hit by quakes as it lies near the junction of two tectonic plates.
In September 1999, a 7.6-magnitude tremor killed 2,400 people in the deadliest natural disaster in the island’s recent history.