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Questions tagged [earthquakes]

Questions regarding a sudden release of seismic waves into the Earth's crust. As well as the causes of earthquakes, their consequences and physics.

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4
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2answers
85 views

Could an earthquake on flat land still kill someone without any buildings/boulders or such near by?

Suppose you were sitting near the epicenter of an earthquake, sitting down on flat land without much else near by, maybe some grass. Is it still possible that say, a magnitude 8 or 9 earthquake would ...
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2answers
51 views

Is there a general equation to know how big of an area is affected by an earthquake?

If you visit USGS earthquakes listing, you get 3 points of information for each earthquake: Location, depth, magnitude. My question is, is there a way to approximate how big of an area is affected? ...
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1answer
28 views

Is it reasonable to approximate the swinging building (base of the building) during an earthquake to a simple harmonic motion?

I am thinking of making a model of swinging building during earthquake and study the methods to minimize the swinging. So does it even makes sense to approximate the swinging buildings (the base of ...
12
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3answers
2k views

Would the shaking of an earthquake be visible to somebody in a low-flying aircraft?

If you are in an airplane well above ground level, but low enough to see the faces of people relatively easily, and an earthquake happens, will you see the ground shake?
3
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1answer
50 views

What is the lateral ground acceleration, at the fault line, during a strike-slip earthquake?

I've read that peak lateral ground acceleration for magnitude 7 - 8 earthquakes is ~1 g at the epicenter (is that correct?), but I'm wondering if it might be significantly higher right at the ...
2
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3answers
87 views

Is this series of earthquakes near Broome, Australia normal?

There have been a series of earthquakes (some strong) near Broom, Western Australia. See this screenshot of the Geoscience Australia earthquakes map: I didn't believe there were any faults around ...
0
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2answers
56 views

Why is it hard to predict earthquakes?

An analogy I came up with is: Predicting earthquake strength and timing is like throwing a sheet of glass on the ground and predicting how many pieces it will break to and where they'll end up. Is ...
2
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1answer
51 views

What is the vertical axis of this waveform shown in this tweeted IRIS GIF?

This IRIS tweet shows a video of siesmic waves from the recent M6.4 Earthquake in California rolling across the US. I've made a small GIF to give the idea but the "GIF" in the tweet shows the whole ...
2
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1answer
48 views

Do earthquakes produce folds on rocks?

Earth rocks are frequently folded at surface. Folds in alternating layers of limestone and chert in Crete, Greece. Source: commons.wikimedia Are earthquakes the main mechanism ...
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0answers
15 views

Hi, is there good reference this raw earthquake data to covert into PGA, PGV and etc?

Is there good reference or software that these earthquake raw data will transform into strong ground motion such PGA, PGV and PGD. Thank you!
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1answer
75 views

What are these basal rip up clasts in North Dakota?

Ther's an graph that appears that the KT asteroid turned the rocks into rubble 3000 km away, else there was a rain of big rocks from the sky. What are the rip up clasts and what is the way they were ...
3
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1answer
46 views

How do I get the velocity of the P-wave or S-wave without using the travel time graph?

I'm trying to write a program that would determine the magnitude and epicenter of an earthquake. From http://www.dartmouth.edu/~ears5/handouts/EQ_distance.html, the distance of the epicenter can be ...
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0answers
20 views

How can shake amplitude influence the damping ratio and resonant frequency of a soil base structure?

I have performed an experiment using a shaking table to simulate the response of a soil base structure to an earthquake. A multi-floor structure was placed on a sand (90% relative density) bed and the ...
9
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1answer
108 views

Could an earthquake create a design in a sand pendulum?

Is it possible for an earthquake to generate such a design in a sand pendulum during an earthquake? I saw an article online describing the story of a shop owner finding one of his pendulums had ...
3
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1answer
97 views

What is the largest earthquake attributable solely to volcanic activity

I was recently and for the first time caught in an earthquake. This being my first time, I freaked out and had no idea whether the building was going to collapse or not. I was later told that this ...
1
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1answer
46 views

Coal fires affecting seismic activity, and also volcanoes

Can coal fires cause earthquakes to happen, or possibly prevent or postpone earthquakes? Also can coal fires trigger(or prevent) volcanic eruptions by affecting flow of magma underground or by some ...
5
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1answer
82 views

largest earthquake not in a subduction zone

Whats the largest earthquake since 1900 that was not in a subduction zone (not a megathrust). Wikipedia says that Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust ...
5
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2answers
74 views

Would epicenters in less-deep areas of ocean tend to reduce the impact of a resulting tsunami somehow (wave “breaks” before getting there?)

I just felt an earthquake at in a 6 floor building in Taipei, where I am familliar with how they have felt over the years. This one felt particularly vertical, and made me feel queezy, while most ...
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0answers
24 views

Are Indonesian 2018 earthquakes related?

Indonesia had multiple major earthquakes this year A series of earthquakes in Lombok between July and August, including a 7.0 mainshock The 7.5 earthquake + tsunami in Sulawesi, September 2018 A 6.0 ...
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1answer
178 views

How likely is that next big earthquake (and tsunami) will hit Philippines again?

We recently had an earthquake in Bali (August 5th 2018), then in Palu, Indonesia (October 1st 2018). Considering the distance and time between Bali and Palu, is it more likely that it will be near ...
4
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0answers
39 views

How do I generate a Moho depth model from seismic refraction data?

There are several permanent seismograph stations in Eastern Canada that have been recording arrival times for over 25 years. Using refracted Pn arrival times from natural earthquakes I would like to ...
8
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1answer
148 views

Seeming correlation between time of day and earthquakes

I live in a generally geographically active area (Southern California, near the San Andreas fault, if that matters), that has had two relatively minor earthquakes that I have felt in the last week (in ...
8
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1answer
88 views

Are strong deep earthquakes that result in minimal impacts common?

Happened to see notice of fairly strong earthquakes near Fiji and Peru within the past few days, and thought I'd find they had been fairly damaging... only to find the impacts were quite minimal. ...
4
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1answer
200 views

Why do major earthquakes keep happening in Lombok recently?

So I've been following the situation in Lombok, Indonesia from both online news and friends on the ground. One thing that I can't seem to figure out is why there are so many earthquakes over an ...
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2answers
445 views

Why do some earthquakes and volcanoes occur within plates?

I know that volcanoes and earthquakes occur on plate margins. But, do some of them also occur within plates?
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0answers
46 views

Seismology - PPV / VDV from geophone waveform data

I'm using an inexpensive seismometer to try and measure the effects of local HGV traffic on buildings. The device is connected to a Raspberry PI that has a Cirrus Logic Audio Card. The signal is fed ...
4
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1answer
57 views

Catalog of all significant earthquakes since 1900?

Where can I find a list of all earthquakes that happened on Earth since 1900?I need time, longitude/latitude, and power -- preferably in .csv format.
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1answer
199 views

What would a graph of magnitude >7.5 earthquakes over last 400 years compared to Grand Solar Minimums look like?

I am a novice here and I really appreciate the graph of magnitude >7 earthquakes related to 11(22)yr solar minimum cycles. I was wondering what the correlation would be (if any) if we changed the ...
11
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1answer
374 views

Did the Geothermal Power Plant contribute to Pahoa's Lava Fissures?

There was lava in the area near the wells that the Puna Geothermal Venture facility created. The plant has nine wells that run as deep as 8,000 feet, according to Wil Okabe, managing director for ...
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0answers
42 views

Applicable seismometers data?

I need to study low frequency range of seismic waves (~ up to 0.07Hz). Is it correct to use accelerometers data to compare with synthetic seismograms. Synthetic seismograms are calculated up to 0.07Hz....
3
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0answers
69 views

Is the probability distribution of earthquakes memoryless?

What I want to know is more specific than the title: If a city sits on major fault lines (let's say Tehran), and has a history of severe earthquakes (greater than 7 magnitude) once every 150 years in ...
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0answers
46 views

Interpretation of horizon display

I am currently working on a project that involves using seismic attributes as input parameters in a neural network for estimation of porosity and permeability for a reservoir. Now, I need to correlate ...
4
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2answers
1k views

Why do loose, soft soils amplify earthquake vibrations rather than dampening them?

Areas where the buildings are built on top of a deep layer of loose sediments are widely recognised as being more prone to earthquake damage (all else being equal) than areas where the bedrock is ...
4
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0answers
61 views

Conversion of body wave magnitude to moment magnitude

I have been tasked with homogenizing a catalog of events obtained from the USGS website, however, the data is a mix of different type of magnitude measures. How do I convert the different type of ...
3
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1answer
268 views

Which type of seismic sensors usually used in Earthquake Early Warning?

As I'm a newbie in seismology and related area, I would like to know which type of seismic sensors usually used in earthquake early warning systems?
5
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2answers
604 views

Megathrust earthquakes on subduction zones

I am a beginner in geology and earthquake studies, and learning about subduction zones recently. Question is: do large earthquakes (sometimes referred to as megathrust quakes) occur on any point in ...
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1answer
3k views

Is there any correlation between Grand Solar Minimums (GSM) and earthquakes? [closed]

I've found many claims arguing that the periods of minimum solar activity are associated with increases earthquakes and volcanic activities. Some of these claims are supported by articles in ...
3
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1answer
207 views

Seismogram deconvolution in SAC

Good day! I have a problem replicating a result. Let us consider the top plot here: On the plot, velocity is in mm/s. I think the problem is to remove instrument response correctly. I downloaded ...
5
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2answers
347 views

2018 Swan Islands earthquake tsunami

How come the strike-slip 7.6 M earthquake, occurring January 9th, 2018, produced no tsunami? Has there ever been any produced in this region?
0
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1answer
142 views

Earthquakes PGA/PGV in time?

Good day! On USGS web-site I can get co-called PGA/PGV (Peak Ground Acceleration/Velocity) values in the region of earthquake. It is possible to get the map of velocities with respect to time (to see ...
2
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2answers
178 views

Why are earthquake considered spot things?

As far as i know earthquake is result of movement of earth crust layers and release of energy at these locations and movements at faults. So i think its happens somehow along a line or in a wide ...
4
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1answer
99 views

What is a “tar shower?”

I'm reading about Sodom and Gomorrah on Wikipedia when I come across this: "One such idea is that the Dead Sea was devastated by an earthquake between 2100 and 1900 BCE. This might have unleashed ...
2
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0answers
214 views

How to calculate seismic moment from seismograms?

I was told that Seismic moment is determined by the observed spectral levels of the receiving waves. But I don't quite understand what it means. How is this done in practice? Do you need ...
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0answers
119 views

Possibility of Domino Effect

Is there any likelihood that an earthquake could trigger a volcanic event? I'm thinking that because the Pacific tectonic plate nearly coincides with the "ring-of-fire," particularly along the west ...
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1answer
195 views

Can we predict the earthquake before it occurs a while? What is the maximum period?What are the signs of an earthquake soon?

I want to know the signs before earthquakes and how long it would talk
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0answers
64 views

What caused the earthquake in Kuwait on Nov 12, 2017?

What are the causes of the earthquake in Kuwait on Nov 12, 2017?
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1answer
186 views

Does the Composition of Rock Near the Epicenter Affect the Effects of an Earthquake?

Aside from the earthquake triggering a quick clay landslide, is there anything else notable?
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1answer
152 views

Lights associated with earthquakes?

According to the New Madrid, Missouri web site, during the 1811-1812 earthquakes there were reports of lights coming from the ground due to quartz crystals being squeezed. They call this phenomena “...
4
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1answer
318 views

What is that spooky humming sound heard in earthquake footages?

In most of the earthquake footages filmed outside during the earthquake that hit Mexico City on September 9, 2017 there was a distinctive streak of hum in rapid succession that could be heard in the ...
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0answers
355 views

Effects of Mexican Earthquake in San Andreas Fault Line

Could the recent 8.1 Magnitude Earthquake at the Cocos and Nazca plates off the Mexican coast have a knock on effect to the Pacific and Juan de Fuca Plates further north at the San Andreas Fault Line?