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

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.

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