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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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 ...
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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 ...
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577 views

Where are earthquakes felt more: on top of a building or on the ground floor?

I have this notion that at the top, the building will be more likely to shake than at the bottom, where it is grounded. So, how does it work with an earthquake? Who would be more likely to perceive a ...
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1answer
1k views

Why do human populations concentrate near fault lines, volcanoes, etc.?

I've noticed that many places with large populations tend to be prime zones for natural disaster. Examples: Silicon Valley = earthquakes, Houston = hurricanes and floods, Japan = tsunamis and ...
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2answers
106 views

Is there any case that changed from earthquake safe zone to danger zone?

Is there any case that changed from earthquake safe zone to danger zone? As plates move, I think that earthquakes belt will change over time. But is there really a case in which the earthquake-safe ...
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1answer
260 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?
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2answers
114 views

Earthquake database for fault

I am trying to understand Deterministic Seismic Hazard analysis for which I believe seismic waves corresponding to a seismic sources (such as faults) are required to prepare the Gutenberg Richter ...
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2answers
561 views

Seismometer records ground displacement or acceleration

I believe Seismometers record ground displacement. However, I have also read in certain articles that this can be ground displacement or acceleration depending on the frequency of the seismometer. ...
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1answer
4k views

What happens if a magnitude 13 earthquake occurs?

What would happen if a Richter magnitude 13 earthquake occurred? I read (at http://www.tulane.edu/~sanelson/Natural_Disasters/impacts.htm; about halfway down the page) that if a comet were to ever hit ...
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1answer
45 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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1answer
586 views

Evidence for “earthquake storm” at the end of the Bronze Age

The decline of the large population centers around the eastern Mediterranean at the end of the Bronze Age has been associated with a set of large earthquakes ("earthquake storm") occurring between ...
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1answer
93 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 ...
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1answer
193 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 ...
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1answer
216 views

How could an earthquake be stopped once triggered?

A fault that ruptures causing an earthquake, can cause a chain reaction of dynamically triggered earthquakes in nearby faults, thus causing a much larger seismic event. What could be some unlikely ...
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64 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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102 views

What is the plausability/legitimacy of the San Andreas Fault 'Big One' Megaquake mechanism?

In the ScienceAlert article "New estimates suggest the 'big one' in San Andreas could be much worse than we thought" they make the claim that: Researchers have forecast a mega-quake running the ...
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3answers
801 views

Why is a mild earthquake often mistaken as dizziness or vertigo?

Is it due to the longitudinal nature of the seismic waves? When a heavy bus or truck goes by at high-speed, the shaking in nearby ground is not mistaken as dizziness, rather the feet and body feel a ...
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2answers
63 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 ...
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2answers
177 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 ...
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1answer
40 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 ...
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1answer
41 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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1answer
526 views

How to find the magnitude of earthquakes roughly if we know the Richter scale magnitude of epicenter?

Please help me roughly estimate the magnitude of a quake at a distance d (for example 300km) from the epicenter if the magnitude at the epicenter is m (7 at richter scale) is known.
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1answer
331 views

How to calculate cumulative moment magnitude?

What is the proper way to calculate cumuluative moment magnitude if I know the moment magnitude of several earthquakes?
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1answer
160 views

Are the other causes of an earthquake (e.g. volcanic eruptions) the cause of the “sudden slip” which is the main cause of an earthquake?

I am to deliver an informative speech about earthquakes in class. However, I was not the first to talk about earthquakes and his discussion of the cause of earthquakes is different from mine. He ...
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1answer
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Seismology: What causes an earthquake? [closed]

I am doing a research on earthquakes but I cannot fully understand what causes earthquakes. "Caused by a sudden releases of energy by the Earth's crust, causing seismic waves which causes the ...
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1answer
70 views

Hazard event predictions. Examples of predictions causing more harm than good

Could anyone give me any examples of attempts to predict earthquakes AND tropical storms that have caused more harm then good (e.g: because an area was predicted to have low levels of risk and ...
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1answer
171 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
274 views

Fault representation

In most illustrations and diagrams of the types of faults, there is always something similar. I noticed that there is a side of the hanging wall and foot wall which is slanted. We're supposed to make ...
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1answer
47 views

Is there a formula to compute the destructiveness of an earthquake?

I am trying to find out if there is a way to compute if an earthquake is destructive. I am looking for a threshold formula which depends on magnitude and depth for example ...
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1answer
66 views

Does the increasing number of significant earthquakes relate to increasing population density in earthquake zones?

I've discovered that there's two different sets of data for earthquakes - one for actual number of earthquakes, and ones for only significant numbers of earthquakes. For example, in January 2016 the ...
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19 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 ...
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14 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 ...
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207 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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112 views

Can hurricanes set off earthquakes?

Large hurricanes can show up on seismographs. Do they do this by shaking the ground with wind? Moving large amounts of water putting weight on the tectonic plates? A large earthquake is the result of ...
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Comparing the 4th of August 1998 earthquake to the 16th of April 2016 earthquake in Ecuador

I'm doing an assignment where I'm comparing the two mentioned earthquakes, and trying to figure out which factors played a role in the amount of casualties. In the 1998 earthquake there were only ...
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33 views

Earthquake data acquisition Geosig VE-53

Is it possible to receive data from a Geosig VE-53 to a PCI data acquisition (serial port) connected to PC and without using a recorder?
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1answer
184 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 ...
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1answer
29 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
44 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 ...
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2answers
564 views

Spatial extent and predictability of various hazards.

My question concerns the following three hazards: earthquakes, hurricanes and drought. In terms of spatial extent (wide spread, limited), I believe that earthquakes generally have the most limited ...
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1answer
73 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 ...
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1answer
1k views

Can large earthquakes happen few times at same place(in days)

I want to know if large earthquakes can happen twice in the same place? I live in Istanbul/Turkey. In Canakkale/Turkey too many earthquakes happen for days! I know it is normal for this region but 4.8 ...
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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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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 ...
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40 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....
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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 ...
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113 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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63 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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354 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?
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How did the The Fukushima Nuclear Disaster affect Japan's vegetation? [closed]

I am working on an important project please help!