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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3answers
842 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
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 ...
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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 ...
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4answers
2k views

Can mining trigger earthquakes?

Are earthquakes more common in mining regions than they would otherwise be? e.g. is the frequency of earthquakes in those regions different when mining is occurring than when it is not? I am ...
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1answer
262 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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1answer
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Using accelerometer as a seismograph

I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in ...
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2answers
337 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?
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0answers
214 views

How to compute the earthquake occurrence probability under ETAS model

I have fitted an ETAS model (unmarked) with an independent exponential magnitude distribution to a set of earthquake data. However, I do not know how to calculate the probability of the earthquake ...
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1answer
194 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 ...
4
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1answer
2k views

Can two earthquakes happen at the same time?

I wanted to know if two earthquakes can happen at the same time in the same area? I "think" this can happen, but I'm not totally sure? I understand tectonic plates sliding against each other can cause ...
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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 ...
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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 ...
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2answers
10k views

How to compare earthquake magnitudes

On the USGS website, it says Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; However my book says ...
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1answer
95 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 ...
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0answers
210 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
116 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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0answers
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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1answer
179 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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2answers
579 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. ...
3
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2answers
116 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 ...
4
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1answer
299 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?
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0answers
113 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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3answers
2k views

What are the distinguishing features of an “artificial seismic wave” (e.g. a large underground explosion)

IN the NPR news item North Korea Possibly Conducts Sixth Nuclear Test, South Korea Says: The U.S. Geological Survey says it detected a 6.3 magnitude "possible explosion" near Sungjibaegam, North ...
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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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612 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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5answers
4k views

Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (link)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (link)--let's assume it ...
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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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1answer
345 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
124 views

Has the Olema earthquake fence continued to spread apart?

The earthquake fence at Olema shows the sudden transform motion along the San Andreas caused by the 1906 earthquake. 110 years on, has there been ANY additional displacement?
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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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1answer
287 views

How to interpret seismic interferometry data?

Here is a screenshot of coseismic interferometry measurements of the 2015 Nepal earthquake. What does it mean? The star is the epicenter of the earthquake. The screenshot was taken from the UNOSAT ...
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1answer
686 views

seismic wave detection standing at the epicenter

If a person is to stand at the epicenter of an earthquake. Is it true that he would not detect P-waves nor S-waves echoing off the mantle core boundary? Since if P-wave that enter perpendicularly ...
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2answers
108 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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0answers
103 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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1answer
487 views

Is it possible that the recent droughts are signs of epic crust failure? [closed]

The full question is: Is it possible that the recent, successive, long droughts from Australia to the West Coast of both American continents are signs of epic crust failure? The question is aimed ...
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2answers
614 views

Why did it take so long to discover the volcanic nature of mid-oceanic ridges?

I just read this article and was astonished to see the following: Oceanographers stumbled on [the mid-oceanic ridges'] volcanic nature in 1973. What I find surprising is how recent that is. ...
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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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2answers
695 views

What would happen if magma flows into a very large oil deposit?

If there were an earthquake that somehow cause a crack in the earth and allowed a significant amount of magma to flow into a very large oil deposit. With that high amount of explosive energy that ...
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1answer
67 views

Is “seismic energy released” a regionalized variable and can be analyzed using geostatistics?

In geostatistics, we can assess and analyze regionalized variables. Tectonic stresses releases in seismically active regions by occurring earthquakes. We can calculate and estimate the seismic energy ...
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1answer
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Can climate change cause earthquakes, tsunamis, or volcanic eruptions?

Different scientists have brought forth a theory that climate change can cause earthquakes, tsunamis and volcanic eruptions. For example: Professor Bill McGuire of University College London in his ...
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2answers
157 views

How do they know the 2016 Kaikoura (NZ) Earthquake was 'complex', involved six different faults?

The BBC news article New Zealand quake: The geological impact of a 'complex' tremor says: The powerful earthquakes which hit New Zealand were some of the most complex ever recorded, say scientists. ...
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1answer
596 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
751 views

Where does the 2015 Nepal earthquake rank amongst earthquakes since 1900?

Wikipedia provides a list of deadly earthquakes since 1900. Where would the April 2015 Nepal earthquake (magnitude currently estimated as 7.8 or 8.1) rank in this list, in terms of magnitude?
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2answers
176 views

Does the moon have any affect on earthquakes being created? [duplicate]

Here, in New Zealand, we just had a 7.5 magnitude earthquake hit. Alot of people are saying that the super moon caused this. I have doubts as to the super moon actually 'causing' it but could have it ...
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4answers
3k views

Are there any other earthquake magnitude scales other than Richter's?

There are sometimes confusion about the magnitude of Earthquakes. What scales, other than Richter's, are used to measure the magnitude of an earthquake? Is there a scale where magnitude 9.0 is ...
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1answer
82 views

Is the concept of seismogenic zone still relevant after the 2011 Japan earthquake?

The concept of subduction seismogenic zone, where megathrust seisms occur in a layer between an upper and a lower limit is well documented in the 1990/early 2000 literature : Some example : Pacheco,...
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1answer
136 views

Relationship between tides and earthquakes

Ide et al. (2016) suggest that earthquakes (especially those of high magnitudes) are more probable during periods of high tidal stress (during full and new moons). While they show a comprehensive ...