Experience the sound of a powerful Earthquake

Strong Motion seismometer that measures accele...

Image via Wikipedia

Thanks to the great service of USGS, we are able to share the sound of a couple of earthquakes to our readers.
As every earthquake has it’s own fingerprint, the sound  going together with it can be seriously different.  Depending on the  Magnitude, rock material, fault lines, etc. the frequency can be low or high and the sound can be short or rolling.

It may be easier to hear the small triggered earthquakes than it is to see them. The Landers earthquake is far from the seismometer so most of its high frequencies have died away before the waves reach the seismometer. But the small earthquakes have small fault areas and therefore produced high frequency energy and because they are near the seismometer this energy has not died away.

Listen to the seismogram recorded at the Long Valley Caldera and see if you can hear the small earthquakes (high frequency bursts) despite the low rumble of the distant large earthquake. Click the sideways triangle (or play button) to hear the sound.

If you are having trouble picking out the small nearby earthquakes, listen for the two very close to the end and then listen to the seismogram again.

Listen to the seismogram recorded at the Long Valley Caldera and see if you can hear the small earthquakes (high frequency bursts) despite the low rumble of the distant large earthquake. Click the sideways triangle (or play button) to hear the sound.

Long Valley Caldera Seismogram

Earthquake sound 1

If you are having trouble picking out the small nearby earthquakes, listen for the two very close to the end and then listen to the seismogram again.


Here are two more seismograms of the Landers earthquake. One is recorded at Parkfield near Paso Robles and the other is recorded at the Geysers north of San Francisco. Only one of these areas had small earthquakes triggered by the Landers event. Can you tell which one?

 

Parkfield Seismogram

Earthquake sound 2

Geysers Seismogram

Earthquake sound 3

Advertisements

Indonesia massive M 7.5 earthquake – Seismographs worldwide turn black

Awaiting more information on South Pagai, we hope our readers will take a look at the

LIVE SEISMOGRAM OVERVIEW page from USGS.

All seismographs worldwide  are coloring black from this massive earthquake.

From Alaska to Antarctica, all seismographs picked up the waves from the Mentawai Islands quake.
The waves did travel through the  earth.
Only the time of recording differs from place to place.

Latest news on this massive earthquake – Click here

Yogyakarta (Java) fears an explosive eruption of Merapi volcano

Merapi in 1930

Merapi volcano in 1930, Image via Wikipedia

Excerpt of an article in the Jakarta Globe

Lava from Mount Merapi in Central Java began flowing down the Gendol River over the weekend, signaling an eruption could be imminent, a geologist said on Sunday.

The volcano, one of the world’s most active, last erupted in June 2006 shortly after the Yogyakarta earthquake, when a pyroclastic flow, or a fast-moving cloud of superheated gas, ran down its slopes and killed two people.
Pyroclastic flows can be devastating for goods and all living creatures near the eruption crater.

But Surono, head of the Volcanology and Geological Disaster Mitigation Agency (PVMBG), said the distension of the mountain’s slopes was much more rapid this time around, indicating a higher-pressure build-up of gas and hence a much more explosive eruption.

“We believe Merapi will erupt explosively, as it did in 1930, and not just spew gas like in 2006,” he said.

“However, that scenario is only a guess. No one really knows when Merapi will erupt and how much volcanic material it will spew out.”

The eruption in 1930 wiped out 13 villages on the slopes of the mountain, killing around 1,400 people.

Merapi volcano lies the backyard of Jogjakarta, one of Indonesia’s most important cities.
Armand Vervaeck, host of this blog,  has climbed Merapi volcano a couple of years ago and witnessed the crater rumble from first hand. A truly fascinating volcano.

 

We encourage reading the full article by clicking on this link.

Indonesia orders evacuation of people living on the slopes of the Merapi volcano

Mount Merapi in Central Java.

Merapi volcano - Image via Wikipedia

Excerpt from an article in the Jakarta Globe from today

Indonesia raised its alert for Mount Merapi to its highest level on Monday and ordered people living near the rumbling volcano to move immediately to safer ground.

Seismic activity has escalated dramatically at the volcano on the densely populated island of Java, with increasing lava spurts and about 500 multi-phased volcanic earthquakes recorded over the weekend, officials said.

The state office of volcanology upgraded its alert level to red at 6:00 a.m., signaling an eruption could be imminent.

The magma has been pushed upwards due to the escalating seismic energy and it’s about a kilometer below the crater,” government volcanologist Surono said.

People had been ordered to evacuate a danger zone of 10 kilometers from the crater of the 2,914-meter mountain.

We encourage reading the full article by clicking on this link.

Your earthquake “FELT” report is of very big importance for science

Earthquake-report.com will from now on encourage FELT reporting from his readers.

Most people are not aware of the importance of their cooperation in reporting their FEEL experiences to the science organizations. The best developed is certainly USGS who gets a big number of felt reports for many earthquakes.

EMSC-CSEM is the European counterpart of USGS and is also a very important agency who does follow earthquakes worldwide and makes outstanding reports with their scientific data.

From now on, Earthquake-report.com will put a FEEL link behind every earthquake in order to have the form always at hand if you have experienced the earthquake yourself.
If you opt to describe what you felt (in your local language !) your individual story can be found on the internet in the EMSC-CSEM website.

Why a FELT report ? Does science doesn’t know it all ?
Earthquake science does know a lot but far from everything.
Predictions are far from being accurate as no scientist will know when and how strong an earthquake will strike. The places above fault lines are better and better known, but nobody knows when the rope will break apart.
The way people are experiencing an earthquake is also totally different with each earthquake.  Depending on the place where they live, the scientific components of a quake, the house they live in, etc every earthquake is experienced differently.
At earthquake-report.com we have noticed continuously that users from our QUAKESOS iPhone Application react totally differently as we sometimes expect. Smaller magnitudes are sometimes experienced as a more powerful earthquakes and bigger Magnitudes are hardly noticed.
Filling up your FEEL form will give science a bigger understanding of the human impact versus raw earthquake data.

The forms are rather extensive, but we encourage filling them up as good as possible as every detail is important for scientists.

Local press articles on the Gulf of California M 6.9 earthquake

Courtesy Noroeste.com

The 2 Mexican provinces who are closest to the epicenter are the provinces of Sinaloa and Baja Calofornia.
Baja California Sur has a population of 512,170
Sinaloa has a population of 2,608,442
Local newspapers in Sinaloa are mentioning that people ran on the street in panic.
The building of the Ministry of Justice has been evacuated as a precaution.
Based on the reports from the closest area near the epicenter NO major damage or injuries are expected or reported.
As expected by Earthquake-Report.com the earthquake has scared people, but the epicenter was too far away from populated areas to cause widespread damage.

USGS has lowered the Magnitude to M 6.7, originally M 6.9

Please read the full Spanish article in Noroeste.com, el portal de Sinaloa

Please read the full Spanish article in El Sol de Sinaloa

How to easily strengthen Haiti earthquake-prone structures ?

Civil engineers studying the effects of Haiti’s devastating earthquake have concluded that a relatively simple system could be used by officials to quickly decide how to modify existing buildings and construct new ones that would better withstand future quakes.

The system, which uses a priority index to rank reinforced concrete buildings according to their seismic vulnerability, originally was developed in Japan and later adapted for use in Turkey by researchers at Purdue University.

A recent study has shown that the system also is applicable to Haiti. The indexing system could be used to identify which buildings need to be strengthened and to guide the construction of new structures, said Santiago Pujol, a Purdue assistant professor of civil engineering.

The researchers surveyed 170 buildings damaged in the January 2010 earthquake. About 40 percent of the buildings were heavily damaged, and findings showed that about 90 percent of those damaged structures would have been classified as vulnerable if the system had been in use.

“What the index tells you is that for a given-size building, the smaller the columns and the fewer the walls between the columns, the more likely the building is to have severe damage,” Irfanoglu said. “Its strength is in its simplicity and the ease of measuring it in the field.”

The index is a ratio of the combined cross sectional areas of all of the ground-story columns and walls compared to a building’s total usable floor area.

A common flaw seen in the buildings is referred to as “captive columns,” where a wall is attached to a column but does not extend as high as the column, leaving a portion of the column unsupported. This configuration, often seen in school buildings, results in severe damage to the unsupported segment of the columns.

The flaw is widespread in Haiti, as well as China, Latin America, Turkey and many other countries, but buildings could easily be strengthened by reconfiguring the “partial-height” walls, Pujol said.

“The Haitians need to concentrate on fixing the buildings that have smaller columns and fewer walls, and there are many such buildings still standing,” he said. “Secondly, they should modify the buildings that have captive columns and ban the use of captive columns in new buildings.”

About 60 percent of the 170 buildings had captive columns.

“We are sharing these findings with engineers at Haiti’s Ministry of Public Works, and we hope they will be interested in using it,” Irfanoglu said.

Click here to read the full original article from Perdue University

Article Courtesy : Perdue University

%d bloggers like this: