Science topic

# Seismics - Science topic

Explore the latest questions and answers in Seismics, and find Seismics experts.

Questions related to Seismics

According to Newton’s third law, every action is always met with an equal and opposite reaction. When a building exerts a vertical force on the ground (action), the ground, in turn, exerts an equal and opposite force on the structure (reaction), resulting in force equilibrium.

In the case of a building, the weight of the structure (i.e., the force of gravity) applies a vertical downward force on the ground. This constitutes the "action." The ground, in response, exerts an equal and opposite upward force on the building, known as the "reaction." This interaction ensures the balance of forces, keeping the building stable.

However, what happens if the ground exerts a lateral force on the base of the building that exceeds the building's reaction?

In fact, this equilibrium is critical in analyzing the static and dynamic behavior of structures, especially when considering additional and differently directed loads such as wind, seismic events, and other external forces. When the ground applies a lateral force to the base of the building that surpasses the structure’s capacity to react (e.g., through vertical loads and structural strength), the building may lose its equilibrium. This can lead to various failure mechanisms, depending on the nature and magnitude of the force.

If such a lateral force arises from seismic activity or ground displacement, the following phenomena may occur:

**Sliding**: If the lateral force exceeds the friction between the building’s foundation and the ground, the structure may slide across the ground, causing damage to the foundations and possibly the upper structural elements.**Overturning**: A sufficiently strong lateral force can cause the building to rotate around a corner of its foundation, leading to overturning. The likelihood of overturning depends on the height and weight of the building relative to its base.

In addition to the potential overturning of the entire building, vertical structural elements such as columns are also prone to rotational instability. This rotational behavior generates destructive moments at the joints, where vertical elements are rigidly connected to horizontal structural components. These moments induce deformations in the main body of the structural elements, progressively leading to their eventual failure.

This phenomenon is critical in seismic design, as the induced moments and rotational tendencies compromise the integrity of the structural frame, leading to premature failure if not adequately mitigated. The structural system must be designed to resist such moments and rotations through appropriate reinforcement, increasing the resilience of both the vertical and horizontal elements.

**Plastic Failures or Cracks**: If the building is not adequately reinforced to withstand such lateral forces, plastic deformations (failures in structural elements such as columns and walls) or serious cracks may appear in the structure.**Soil Rupture**: If the ground beneath the building lacks sufficient bearing capacity and is subjected to excessive stress, cracks or subsidence may occur, compromising the stability of the structure.

**Seismic Behavior and Earthquake-Resistant Design**

In seismically active regions, lateral forces from seismic loads are often the most critical. To counter these forces, earthquake-resistant design considers factors such as:

- Shear and deformation of walls.
- Adequate foundation design to prevent subsidence, sliding, or overturning.
- Prestressed systems or reinforcements, such as tendon applications, that enhance the building’s resistance to lateral forces.

The fundamental difference in earthquake-resistant design is that it aims to increase the building's dynamic response, allowing it to withstand forces greater than the "natural" reaction it would have without reinforcement.

The newly proposed technology primarily integrates the mass of the structure with the mass of the ground, ensuring that the building’s reaction originates from the ground.

By integrating the building’s mass with the mass of the ground, the proposed technology seeks to utilize the reaction from the ground. This means the ground essentially becomes part of the reaction system, improving the stability and the structure’s capacity to withstand external forces, such as seismic loads.

Instead of relying solely on the strength of vertical elements (columns, walls) and the foundation, the structure "collaborates" with the ground to achieve a stronger and more efficient reaction to seismic forces. This can be accomplished either by using prestressing mechanisms or through other reinforcement techniques that incorporate the ground into the system's response.

This advanced approach could lead to a significant reduction in damage during seismic events if it successfully transfers part of the seismic energy into the ground, rather than being absorbed solely by the structure itself.

To achieve the transfer of seismic energy into the ground, the proposed technology connects the structure to the ground through anchoring mechanisms and tendons, ensuring that the structure’s reaction is transferred into the ground, not just resting upon it. This solid connection between the building and the ground is critical to reducing the destructive forces during earthquakes.

Moreover, increasing the dynamic capacity of walls without increasing mass—which would otherwise elevate seismic loads—is achieved through the use of compressive forces. The walls, suitably reinforced to withstand compressive and shear forces, can better cope with the effects of seismic movements without the need for additional mass.

The integration of the structure with the ground and the use of compressive forces for wall reinforcement represent an innovative approach that could bring significant improvements to earthquake-resistant design.

I am inputting a sine wave of frequency 2Hz as dynamic input for seismic response analysis of reinforced earth wall. Should I use the input frequency or natural frequency of the system as centre frequency for Rayleigh damping? Will I be able to find out the natural frequency using FLAC itself.

According to Newton's third law, for there to be a balance of forces, for every action there must be an equal reaction.

Here's the strange thing about engineers.

The action of a large earthquake is three to four times the weight-reaction of the building, and they expect there to be an equilibrium of forces without bolting the structure to the ground. I offer them an extra force coming from the ground to balance the seismic action and they are still wondering if they want it!

1.Use the small weak cross-sections of beam and wall elements to take the moments at the nodes, instead of using the strong large cross-sections. This goes against science. I use the large strong cross sections.

2. You only use the element cross sections to obtain the earthquake stresses. This goes against science. I use in addition the external ground force to derive earthquake intensities.

3.To increase the strength of the sections you add more reinforcement and concrete increasing the mass which increases the seismic loads without increasing the strength because no matter how many irons you put in the butter the concrete will break once they start pulling.

I am using artificial compression to increase the concrete's active cross section, dynamic, stiffness, and bearing capacity to the lateral earthquake loads and base shear and all shear in general without increasing the mass and by sending the stresses into the ground I am removing them from the cross sections.

4. Concrete in two things does not resist a. tension b. shear. You are forcing it to take tension and shear. Concrete can only withstand compression. But even in compression it can resist compression you have disabled it because as you design only a small part of the cross section receives compression.

I design so that the whole cross-section is active in compression since that is what the prestressing does, secondly I design so that there is no shear failure in the concrete overlay, and I apply compression to counteract the tension which compression is resisted by the concrete.

The new seismic technology aims to solve all existing problems of structures that occur at high seismic ground accelerations.

The method applies controlled artificial compression with a stress ranging at 50% of the strength of the cross-section with a concrete safety factor of 1.5, at the ends of all longitudinal walls of reinforced concrete, applied between the nodes of the top level and the base. It also braces the lower ends of the tension tendons to the foundation soil using expandable anchorage mechanisms, which are activated from the foundation soil level, prior to the construction erection works, using hydraulic tensioners, which apply pulling intensities to excite the mechanisms and open them, which are twice the axial calculation loads.

Hello!

i’m trying to model a portal frame with a tmd attached to it in ABAQUS , subject to seismic excitation. It would be a great help if anyone could provide a step by step guidance in doing so

How I can perform fragility curves in sap2000, for an arch bridge?

I had the 1D model of bridge and the seismic input

The magnitudes of the Marsquakes are given in Richter scale.

Causes of inelastic deformation of reinforced concrete load-bearing structures. 1. Deformation of wall frame and column 2. Torsion of their trunk

The inelastic deformation of the trunk of the vertical elements of the reinforced concrete load-bearing structure and the torsion of these trunks transfer stresses to the nodes by deforming the horizontal elements of the load-bearing structure as well.

These two causes of inelastic deformation I believe can be stopped, 1. by increasing the stiffness of the walls by applying Post-tensioning at the edges of the walls and 2. embedding the tendons in the foundation soil.

Damage and deformation are closely related concepts since the control of deformations also controls the damage.

What is your opinion?

I'm a PhD student researching seismic amplification in a NZ sedimentary basin. I hope that somebody will be able to help me in my interpretation of the 2D seismic lines that traverse the basin. As per the attached image, I am somewhat baffled by the amount confusion in the seismic signals below the surface(shown within red rectangles) that are appearing where I would expect a regular stratigraphic sequence. I have attempted to delineate fault lines but I don't know how successful I am in this aspect. I point out that the mid formation (250-1250m) is consolidated marine sediments, above this mostly sediments from a volcanic source (silts, sands and pebbles mostly unconsolidated).

While the region has historically been understood as passive in terms of seismic activity, this may not be the case as this research may prove.

One of the suggestions for the signal complexity is that the surface region has been so fractured by seismic activity that the resulting unsorted and unstratified volcanic sediments impair the clarity of the signal that is penetrating below.

I hope that someone with experience may have an answer.

The impact of using double and clamp in the arch section of historical bridges on the seismic performance of bridges.

Tarihi köprülerin kemer kısmında dubel ve kelepçe kullanımının köprülerin sismik davranışına etkileri nelerdir?

We know that one of the important members of a 3D Geomechanical Model is in-situ stresses' directions and magnitudes. we can use the seismic data to estimate these parameters in special record mode (Wide Azimuth and Wide-Angle seismic data), but these are not available in all cases, and we have just an ordinary seismic data set which is not processed as anisotropy studies data. So, it is a question that is possible to use seismic data by using AI methods to estimate stress directions and magnitudes?

Thank You

These scientists who are doing this experiment.

They know how to protect the seismic base from the fall of the experiment by placing iron protection scaffolding around the experiment, but they don't have the imagination to realize that this scaffolding can 100% protect the houses from the earthquake.

Instead of making structures with protective shafts and walls they make rocking walls

My proposal for seismic protection in the video.

1. This video design method involves a flexible structure with columns, and within or outside this flexible structure we place a lift shaft, or one or more independent rigid shear walls of reinforced concrete, with appropriately shaped plan sections and with prestressed ends connected to the ground. No large foundations or connecting beams are needed since the moments are taken up by the ground.

2. Independent columns and independent rigid walls mean that they all take their respective seismic loads.

3. We place horizontal seismic insulation at the base to prevent high accelerations.

4. We install strong damping tires to ensure smooth absorption of the impact between the diaphragms of the plates and the walls. This gap between two or more independent structures is increased in height per floor to ensure smooth natural oscillation, because if the gaps were the same, moments would be diverted to the base.

The difference in displacement and impact phase results from many factors of elasticity stiffness and height.

In this method, the displacements of the two independent structures cancel each other out due to the inter-impact and the inelastic deformation of the elastic structure with supports is prevented by the stiff shaft.

5. At their upper ends, the walls have hydraulic jacks connected to the prestressing tendons. When rigid elevator shafts tend to overturn due to displacement, the fluids in the hydraulic jacks heat up because they prevent deformation, converting the kinetic displacement force into heat, creating a smooth elastic seismic damping.

6. The deflection of seismic forces to the ground and the high stiffness of the walls and the bearing capacity of the foundation soil is given and is due to the pre-stressing and connection of the ends of the walls to the ground.

7. This design allows for plenty of light and great visibility.

As per ASTM D4428M-14 and IS 13372 (Part 2): 1992 (RA2001), the Modulus of shear, bulk, and elasticity can be calculated directly from Vp and Vs. How can I calculate specific moduli such as

*based on the cross-hole seismic test (based on the velocity of P and S waves & Poisson's ratio)?***the tangent shear modulus, rotational shear modulus, modulus reduction, constrained modulus, and secant modulus**Please share your thoughts and literature on the above-stated-problem.

If you design a scale specimen to do a seismic experiment. What should you look for to make the experiment reliable?

1.In microscale experiments should you do everything in microscale and the displacement between two points?

2.The models must have the scale within their structure, so that the sub-scale intensity of the earthquake causes corresponding sub-scale displacements that agree with elastic theory ?

If anyone knows the rules of microscale seismic experiments it would be very useful for me to know them. Thanks a lot!

i want to change the seismic start time in Hampson and Russell, i import the data from petrel. In petrel the zero point is not same as the seismic that i load in Hampson and Russell. Is there any way to change it?

I want to train neural networks to evaluate the seismic performance of bridges, but the papers online are all based on their own databases and have not been published. Where can I find the relevant dataset? The dataset can include the following content: yield strength of steel bars, compressive strength of concrete, number of spans, span length, seismic intensity, support type, seismic damage level, etc

Hello,

Is there any public code to calculate the Evolutionary Power Spectrum Density of a non-stationary signal, such as seismic ground motion?

Dear all, this is admittedly a somewhat shallow, language-related question; but I’ve been wondering what would be the best English translation of the word “Geothermie” that is widely used in the German-speaking countries. There are several terms that come somewhat close, such as ‘geothermal energy’, ‘geothermal technology’, 'geothermal resources', or ‘geothermal power’ – but none of them actually mean exactly the same. ‘Geothermal’ is sometimes used independently (similar to ‘seismic’), but that is, strictly speaking, incorrect (well, it is an adjective); likewise, ‘geothermy’ doesn’t seem to be a valid expression. Any suggestions?
Thanks, Martin

Question about how and types of methods to optimize steel structures for seismic resistance

I am a final year Masters's Student from Heriot-Watt University currently working on my dissertation project titled "A THEORETICAL ASSESSMENT OF THE STRUCTURE OF A LIQUID STORAGE TANK UNDER SEISMIC FORCES" with the following objectives:

1. Verification of Current Theories (Housner, Preethi, and Malhotra) of liquid Structure Behavior (sloshing wave height) under seismic forces for petroleum-filled storage tanks using Finite Element Modelling and Finite Element Analysis.

2. Assessment of the possible failure mechanism of the superstructure of the various liquid storage vessels under exposure to seismic forces using Finite Element Modelling and Finite Element Analysis based on the API 650 Design Standard.

3. Proposal and initial assessment of the effectiveness of a Bass Isolation System on the sloshing wave height using Finite Element Modelling and Finite Element Analysis.

Can the

**Ansys modal analysis module**be used to model a fluid-filled storage tank and determine the sloshing wave height along with the impulsive and convective mass components of the fluid based on the application of specific Acceleration, Velocity, and displacement values?Can I subsequently transfer the model to the

**Ansys Static Structural Module**to determine the various resulting stresses that will develop within the tank structure due to the seismic forces and the fluid-structure interactions?If not, can you guys offer any advice on what methodology I should take?

How to differentiate between mud and salt diapir using seismic data?

While traditional science deals with supposedly predictable phenomena such as gravity, electricity or chemical reactions, there is also Chaos Theory which deals with non-linear things that are virtually impossible to predict or control, such as turbulence, weather, the stock market, our brain states and so on.

When there is an earthquake there are too many unpredictable - unpredictable chaos factors in the behavior of the ground and the structure that change the stress measure of each individual structure.

Low-rise structure, mid-rise structure and high-rise structure react differently to the multiple frequencies of ground displacement reaching below the structure.

The direction of the earthquake is unknown, the ground acceleration reaching under the structure and determining the force of the earthquake is unknown, the exact content of the seismic excitation frequencies is unknown, the duration of the earthquake is unknown, a structure can withstand high acceleration for a short duration or low acceleration for a long duration, but cannot withstand high acceleration for a long duration, the magnitude of the earthquake is unknown, the distance from the epicentre of the earthquake to the structure is unknown, the focal depth of the earthquake is unknown, the composition of the ground between the structure and the earthquake which transmits the energy of the earthquake is unknown, e.g. e.g. soft soil increases ground displacement four to five times compared to rock. Even the maximum possible accelerations given by seismologists, which determine the seismic design factor, have a probability of being exceeded by more than 10%.

The correlation of quantities such as "inertia stresses, damping forces, elastic forces, dynamic characteristics of the structure, soil-structure interaction, imposed ground motion" is non-linear and by interacting with each other they change the behaviour and stress of the building.

I am engaged in applied research of seismic structures trying to eliminate and control all these unstable chaos factors lying on the ground and better construction by applying prestressing at the ends of the wall sections in order to reduce the deformation of their frame and increase the strength of their reinforced concrete without admixtures and mass increase which incidentally increases the inertia loads, and on the other hand I am embedding the structure with the ground for the first time in the world in order to rotate the inertia loads into the ground allowing the ground to participate in the response of the structure to the seismic displacements, excessively controlling the chaos of all these unstable factors, while increasing the quality of the foundation soil.

In addition to the above mentioned too, there are three other factors that I exploit to increase the earthquake carrying capacity of structures.

1) I built additional seismic damping mechanisms throughout the height of the building.

2) Decoupling of the elastic columns and beams and plates, from the rigid longitudinal prestressed and butted walls with the ground, allows them to collide with each other at the height of the diaphragms and in this way to cancel out the displacements of the load-bearing structure and the deformations.

3) I exploited the double lever arm of height and width of the longitudinal walls, so that the lever arm of width cancels out the torque tensions that the lever arm of height lowers at the base.

Hi,

I hope you are well.

There are different methods by using them it is possible to predict the response. For instance, we can use Machine Learning methods to predict seismic structural response. For this purpose, it is compulsory to have a reliable range of input data and output data. Then, using the regression analysis we can predict response. This is a functional procedure that is used in the literature. For Structural Engineering, this can be vital because it can decrease computational efforts considerably. Therefore, we won't have to use Finite Element programming (e.g., OpenSees) every single time with a huge volume of computational efforts.

I am looking for software that can predict responses in any field of expertise. If you have seen a kind of software that can predict a response within a second, and also, can decrease computational efforts exponentially in comparison with other methods, I would be grateful if you could share that with me.

Best regards,

Mohsen Masoomzadeh.

The purpose of earthquake engineering is not to build strong and earthquake-resistant buildings that do not experience the slightest damage in rare and severe earthquakes. The cost of such structures for the vast majority of users will have no economic justification.

Instead, engineers focus on buildings that resist earthquakes' effects and do not collapse, even in severe external excitations. It is the most important goal of international standards in the seismic design of buildings.

Below I have mentioned some crucial points in reducing the seismic demand in reinforced concrete structures.

**If there is anything else that is not on the list, feel free to append:**1- Selecting suitable construction conditions with the desired soil type of seismic design

2. Avoid using unnecessary masses in the building

3- Using simple structural elements with minimal torsional effects

4. Avoid sudden changes in strength and stiffness in building height

5. Prevent the formation of soft-story

6. Provide sufficient lateral restraint to control drift through shear walls

7- Preventing disturbance in the lateral behavior of the structure by non-structural components

**Ioannis N. Lymperis .. Independent researcher**

**Abstract**

**The design method of applying artificial compression to the ends of all longitudinal reinforced concrete walls and, at the same time, connecting the ends of the walls to the ground using ground anchors placed at the depths of the boreholes, transfers the inertial stresses of the structure in the ground, which acts as an external force in the structure's response to seismic displacements. The wall with the artificial compression acquires dynamic, larger active cross-section and high biaxial stiffness, preventing all failures caused by inelastic deformation. By connecting the ends of all walls to the ground, we control the eigen frequency of the structure and the ground during each seismic loading cycle, preventing inelastic displacements. At the same time, we ensure the strong bearing capacity of the foundation soil and the structure By designing the walls correctly and placing them in proper locations, we prevent the torsional flexural buckling that occurs in asymmetrical structures, asymmetrical floor plans, and metal and tall structures.Compression of the wall sections mitigates the transfer of deformations to the connection nodes, strengthens the wall section in terms of base intersection shear and shear of the sections, prevents stress at the ends of the walls by introducing counteracting compressive forces. The use of tendons within the ducts prevents longitudinal shear in the overlay concrete, while anchoring the walls to the foundation not only dissipates inertial forces to the ground but also prevents rotation of the walls, thus maintaining the structural integrity of the beams.**

What is your opinion? Is what I write correct?

it is assumed that interpreting 4D seismic data shot over hydrocarbon reservoirs made of carbonates is more challenging than for clastic reservoirs. Then what could improve the value of 4D seismic for carbonates?

Hello, I applied acceleration to simulate seismic in my model, and I don't know how to verify that my seismic wave is absorb by infinite elements, does anyone do verify before?

Thanks,

This is a similar question to a previous posting of mine. I have a range of seismic isochron maps representing different horizons in a sedimentary basin (files attached). I have no further information other than these maps and would like to convert the contours to depth. I point out that the index contours have a depth (in brackets) beside the contour value but I can't work out the intermediate lines. I need to obtain a constant conversion factor and I can't get this from the index values as it changes with increasing TWT.

Also, there a number of parallel lines that bisect the isochrons, are these faults?

Thank you

Dave

Share your perspective on hydraulic fracturing (fracking) regarding its environmental impact, especially considering concerns like water contamination, seismic activity, and the potential economic benefits?

In particular, I'm wondering about its detrimental impact.

Is it possible to have a VP/Vs ratio of less than 1 in near surface seismic studies (using seismic refraction and MASW methods)? If yes, What is the geological and geophysical explanation for this phenomenon?

what steps should i ensure it is done correctly. do i apply it as a link or a spring

We know that at minimum of a group velocity curve, we get Airy phase with large amplitude of surface waves. My question is: Does the amplitude depends on the sharpness of minimum i.e. on |dU/dT| around the group velocity minimum? Here I have used U as group velocity and T is period of surface wave.

Tunnel-forms building is a type of reinforced concrete (RC) building that is constructed using prefabricated forms. The seismic performance of tunnel-forms RC buildings has been studied extensively. They are designed to withstand lateral drift and are structurally sound. However, some research say they are not seismically adequate !

Could we apply chevron bracing technique ? As a damping mechanism for tunnel-forms RC tall buildings.

I have performed a fragility analysis based on Incremental dynamic analysis for the Bare frame and open ground storey frame and full infill frame.

I sent the manuscript to Springer Journal.

Reviewer's comments are as follows:

The research has made some contribution by comparing the seismic fragility of RC frames with and without masonry infills. However, the results need to be justified with regard to following concern:

It is conjectured that the infilled frames performed better. We need more strong evidence for such a claim.

**The numerical analysis results showing the development of relative stiffness and strength between the infills and main frame during the dynamic analysis may be presented.**Also, reference may be made to other researches confirming the statement.My main question is how such an unfavorable element (infill) which detrimentally adds to the stiffness of the structure and causes the absorption of more seismic force, and at the same time is not strong enough to last for the entire seismic event, and even is not ductile to absorb seismic energy, could improve the overall performance.

It is conjectured that the infilled frames performed better.

How such an unfavourable element (infill) which detrimentally adds to the stiffness of the structure and causes the absorption of more seismic force, and at the same time is not strong enough to last for the entire seismic event, and even is not ductile to absorb seismic energy, could improve the overall performance.

seismic loads ,earthquakes and earthquakes dampers

1. The elastic column has the ability to move elastically in the earthquake as it also has the necessary plasticity for inelastic displacements. On the other hand, it does not put down large torques at the base However, the column does not have dynamics like a rigid reinforced wall, and it does not have a second lever arm in width, which reduces the overturning moment. The wall has great dynamics towards the earthquake, it has a second lever arm in width that reduces the overturning moment, but it does not have great plasticity and on the other hand, it lowers large moments to the base due to stiffness and breaks beams and joists. Also, due to greater mass, the inertia of the structure increases and thus the seismic loads. Question Is there a vertical load-bearing element that has a double lever arm, ductility, elasticity, dynamics, and does not transmit its moment to the beams and joists, and is strong towards the intersection of the base, and economical with the minimum steel reinforcement? Yes there is. But they don't use it It is called an elongated wall with prestressed and ground-consolidated ends.

2. If we want to increase the response of the structure to the earthquake, we increase the mass of the concrete by building walls and large beams. We are still increasing the steel reinforcement. Nicely we built a dynamic rigid structure something like a reinforced concrete precast which has great dynamics. Normally it should withstand the earthquake. However, it does not last, especially when the construction is tall. The reasons are as follows. By increasing the mass, we also increase the inertia of the structure and thus the seismic loads. By increasing the height and stiffness we increase the overturning moment These three factors, if they do not overturn the structure, will at least create a small overturning - swelling in the area of the base of the building. The structure losing partial soil support will divert the now unsupported static loads to the beam cross-sections and break them. This happens when we increase the dimensions of the load-bearing organism to increase the dynamic response of the structure. Question There is a solution? Yes, there is a solution. We must increase the dynamics of the structure without increasing its mass, which causes greater inertia. That is, we can increase the linear and transverse reinforcement, and the quality of the concrete, as well as reduce the diameter (not the kilograms) of the reinforcement, in order to achieve greater resistance, in terms of the shear failure of the coating concrete, due to its super strength steel in tension. This they do today and have greatly improved the dynamics and ductility, but greatly increased the cost of steel reinforcement. A steel of diameter Φ/50 has the ability to lift a two-story building with an area of 100 m2 weighing 140 tons, and today they put 8500 kg of steel on the two-story and we have failures in large earthquakes. And this is because the concrete cannot hold the steel reinforcement in it to cooperate and it breaks. Is there another solution? Yes, there is another solution and it is the one I propose. This solution removes 80% of the reinforcement so the construction becomes more economical. This solution triples the dynamic response of the structure to seismic displacements, without increasing the mass, i.e. the inertia that causes the seismic loads, and this happens because the force that counteracts the earthquake comes from an external factor, that of the ground, so it has no mass added to the structure. This solution diverts the seismic loads outside the structure and the structure is not stressed by the earthquake. This solution is called an elongated wall with prestressed and soil-consolidated ends.

I hope the profiles to be as long and detailed as possible, and I will cite them in my paper.

dears, How can I estimation the signal/noise ratio of seismic data by using petrel?

thanks

Quantitative Estimation of Reservoir Dynamic Properties

1. Does 4D Seismic data really complement well production information that remains spatially sparse and temporally dense by essentially offering information on the variations of reservoir properties across the entire reservoir @ a given production time as a function of the varying seismic amplitudes?

2. If the changes in each of the reservoir properties has an independent impact on the seismic data, then, how precisely, the superposition of all the effects caused by the simultaneous variations in any particular dynamic reservoir property could be captured in the absence of quantitatively estimating the simultaneous contribution of each reservoir property to the final observed data (4D AVO)?

I am new to this research field. can anyone please tell me what is the most recent research which is currently emerging in this field?

I need the data for experiments of super-resolution. That is, low-resolution data can be get by convoluted Ricker wavelet with low-frequency, high-resolution data can be get by convoluted Ricker wavelet with high-frequency.

It is not easy to forecast or predict an earthquake and till now there has been no successful prediction in history except one from a Chinese researcher in the mid-70s. But for the last few weeks, people have been expecting that planetary alignments are indicators of seismic events. So being an earthquake researcher I think it is quite difficult to highlight the exact area of the upcoming seismic events with the help of this technique. I need opinions from the scientific community on this topic.

Hello good time To design a seismic isolator for bridges according to the Ashto code, we design a seismic isolator for a design earthquake (1000-year return period) and there are examples of this in the Ashto guide. If the goal of designing a seismic isolator is for MCE earthquake, what should we do? Unfortunately, I still haven't found the solution and method.

I've done the Log Correlation or Well Seismic Tie in HRS, but I want to do the picking horizon and fault in my Petrel. How to import the result from HRS to Petrel? And what kind of format should I use to export it?

Thank you in advance!

I want to process a Well Seismic Tie in Hampson-Russell software, so I need to import my seismic data, well data, check shot, and P-wave. I have the well's coordinates, but the seismic data is on different UTM Zones than the well's coordinates recorded. The well doesn't attach to the seismic data when I load it. Can I change the UTM Zones or it happened because of other issues?

Thank you in advance!

A geophysical model is obtained before inversion process.

The math tells us that the acceleration, depend on the frequency, in the unit of time, X the amplitude of oscillation, and the value of the acceleration X the kilograms of the mass gives us the inertia, and the intersecting base which have the same value. If we multiply the inertia by the height, it gives us the overturning moment of the lever arm at height If the moment of the lever arm in height is divided by the width of the wall which is the second lever arm in width, the overturning moments are reduced according to the width of the second lever arm. So the height along with the acceleration and the mass increases the moments that the wall lowers, while the width of the second lever arm decreases them. So if we want to construct a building which lowers smaller moments we have to do the following. 1) We can't do much about acceleration because it depends on the earthquake. However, we can install horizontal seismic insulation in the construction which reduces the acceleration. But this costs 2) For the mass, we can reduce the weight by using in the masonry instead of bricks and cement blocks the Alfa Block (Aerated concrete) which, apart from being light, thus reducing the weight of the reinforcement and the cost, they also have a lower inertia and overturning moment . In multi-storey and general high-beam constructions, it is a good choice for cheaper, more insulated and anti-seismic constructions. They are not suitable for the construction of two or even fewer floors. 3) For the overturning moment, and the reception of the cutting base, the structure that has a small height and a large width of walls is better. Ideal such constructions are continuous construction buildings made entirely of reinforced concrete (without masonry) or heavy-duty prefabricated buildings. The latter are even cheaper than conventional houses because they are manufactured. But they have a problem, they are dynamic but they are also rigid. Flexible elastic buildings made of columns combined with walls have both dynamics and elasticity and are less vulnerable to earthquake. Usually the columns take the static loads and the walls and the seismic loads. For this reason civil engineers prefer them for the best seismic design. Here comes a question. What can we do to reduce the overturning moment, the bending moment, the moment at the nodes and increase the resistance to the intersecting base, while reducing the construction cost by increasing its seismic resistance? The answer is simple. We buy heavy-duty prefabricated houses, which we compact their sides with the ground, with the mechanism of the patent, and apply prestressing to their cross-sections. With this design method 1) We drop the cost by 30% from conventional houses. 2) We increase the height of prefabricated structures by building skyscrapers (today only ground floor and one floor are allowed) 3) We reduce the number of anchors and therefore the cost of compaction. 4) We increase the speed of completion of the project

Seismic Inversion and Carbonate Reservoir Characterization

1. Feasible to precisely understand the rock properties – from the spatial variations in impedance contrasts – towards estimating the carbonate reservoir properties (away from production well) – using seismic amplitude data?

2. To what extent, the details on the fracture-size, fracture-shape distributions – could be deduced – using seismic responses (spatial variation of impedance contrasts) – towards identifying optimal drilling locations – in a carbonate reservoir?

3. To what extent, the details on the mineral composition and interaction among minerals – will influence – the fracability of a carbonate reservoir – using the approach of seismic acquisition, processing and pre-stack inversion?

If so, then, how exactly to relate the fracability of a carbonate reservoir to the seismic estimates – on the ratio of differential horizontal stresses; the pressure to initiate fractures; and the closure pressure?

4. Have any major limitations - associated with the ‘isotropic’ seismic inversion algorithm – towards estimating the continuous rock properties – of a carbonate reservoir - at the seismic-scale?

5. How sensitive will be – the coupling between ‘rock-physics modeling’ and ‘pre-stack seismic inversion’ – towards ‘value estimation from grid searching’ – in a carbonate reservoir?

6. Feasible to justify the assumptions of (a) linear approximation for reflectivity; and (b) the natural logarithms of P-impedance, S-impedance & density to have a linear correlation – in a carbonate reservoir – towards simultaneous inversion of pre-stack seismic data?

7. To what extent, the simultaneous investigation of rock properties of a carbonate reservoir – along with the interpretation of seismic attribute variations – would really mitigate the contradictions, if any – arising from – having both explicit and implicit relationships between rock and elastic properties of a carbonate reservoir?

8. To what extent, will we be able to achieve the ‘accuracy’ of ‘seismic inversion’ - in a carbonate reservoir?

What are the consequences of not inverting the elastic properties correctly – in a carbonate reservoir (apart from the difficulty of correlating the carbonate rock properties with the seismic attributes)?

Feasible to perform ‘anisotropic inversion’ – in a carbonate reservoir (in the absence of anisotropic measurements @ both log-scale and laboratory-scale, while the seismic data quality @ far offsets remaining poor)?

9. How easy/difficult will it remain - to capture the impedance contrast - at the fracture-matrix interface - in a carbonate reservoir?

A network of long-term seismic stations has been deployed on the Earth's surface (slide attached). The second slide shows the data for the Yakutsk station (Russia). The beginning of vibrations is 06/06/2011, the end is 02/17/12. What it is?

Iraq regions seismology data are quite contraventional, and yet no real study has been conducted, to draw the proper steps to establish such maps. Baghdad Captial undergoing construction of Low-to-Medium Rise Building, which desperately need such reference maps (Building Design Codes regulations) which effects/threat life of millions of peoples ...

The seismic data from ocean bottom seismograph is used to image the structure of crust and mantle below the ocean or sea. Whatmore, the multi-channel seismic data can also image the crustal structure. I want to know whether the difference occurs between both. if has, then what is the difference? For example, the seismic acquisition or seismic processing.

In all countries, the use of wood as a structural material is present to a greater or lesser extent.

I wonder.

a- In your countries, what are the regulations for the design of timber structures called?

b- Is the design done by ASD or LRFD?

c- Are seismic demands taken into account for the design of timber structures?

Please feel free to provide a reference to such documents.

Thank you

I'm a hydrogeologist, I'm modeling fracture flow. Some fracturing in hard rocks (e.g. granite) occurs due to seismic/tectonic activity. I'll be really thankful if somebody gives me an information/articles concerning fracture development/fracture connectivity based on seismic waves/ amplitude of tectonic movements, etc. in hard rocks.

This is a question about earthquake amplitude attenuation.

With your experience of observing earthquake waveforms or simulating ones, I hope you will give us some insight on that matter.

I'm trying to simulate the PGD/PGA attenuation along a given azimuth of an earthquake magnitude 5.5, reverse fault (S:215 D:50 R:84), with point source simulation.

The process is to simulate synthetic seismograms at each stations separated with equidistance (~5km). A 1-D tabular velocity model is used.

We consider only the horizontal components (radial and transversal); and the PGD/PGA is the maximum between them.

The results I'm getting are strange for me.

The figure attached shows the PGA amplitude of 40 stations in two directions: azimuth 45° and azimuth 125°.

I was expecting a constant regular attenuation from the nearest station to the farthest one. Instead, I got two sudden decrease followed by an increase in the amplitude (around 56km and 130km for the example shown in the figure attached).

I did run several tests and this anomaly (if it is), doesn't seem to be affected by the event depth or with seismic nuting.

I would like to know if in such condition (ideal conditions without any amplification factors at the surface) we expect an amplification in amplitude (due to ordinary wave behavior such us multiple) ?

Or is it expected, especially with reverse faults? Since the chosen azimuths (45° and 125°) are ~ parallel and perpendicular to the strike?

Or is there any other explanation or error that I'm missing.

Thank you in advance for your help

I am having trouble importing 2D seismic data into Petrel, as in the SEGY files the X- and Y coordinates are all set to zero (see picture).

However, I do have a shapefile indicating the location of the different 2D seismic lines. Is there any way to use this to import my seismic data? The problem is that due to the X- and Y coordinates all being zero, I get the following error;

Dear all

Is there any hard academic literature on the historical application of seismic inversion technique for lithology prediction?

Thank you

B ZEGAGH

Hi. I wish to understand the codal provision from IS 1893 Part-1 and IS 4326 which states the minimum separation gap for adjacent structures. Let us suppose I have a 10 storey moment resisting RCC frame that has a maximum displacement of 70 mm towards the right and a stiff 5 storey RCC structure having a displacement of 2.5 mm (both values approximated to the nearest multiple of 5 for ease). The response reduction factor, R = 5.

A confusion I have right now is from Table 1, IS 4326 where we see something like Gap Distance/Number of storey. For a moment resisting concrete frame, this value is 20 mm. In the case of the sets of structures that I have mentioned, should I use 20*10 = 200 mm (total number of storeys in larger building = 10), 20*5 = 100 mm (the maximum storey level for smaller structure = 5th storey) or simply 20 mm

What seismic gap should I provide between them? Attached for reference are excerpts from the mentioned codes for reference. Thanks in advance

Seismic moment gives us the release of the energy during earthquake. If this could relate to the PGA expected at site, we could estimate the PGA from moment magnitude itself. Probabilistic seismic hazard analysis is an elaborate procedure to get this but a direct relation can save a lot of time and calculations.

Recognizing depositional sequences is the first step in seismic interpretation for reservoir management. Wu and Hale (2015) presented the “unconformity likelihood” attribute for revealing unconformity surfaces bounding seismic packages so far.

Can anyone please tell me which software program tool I should use to separate unconformities (marked by toplap, onlap, & downlap) on seismic data?

Thanks, and best regards,

Mohammad Abdelwahhab

I am doing my MTech thesis on topic “ANALYSIS OF SEISMIC SEPARATION GAP BETWEEN TWO ADJACENT REINFORCED CONCRETE BUILDING” and i am planning to use FVD250 between two adjacent buildings, so what will be the cost of one single viscous damper and is it good idea to use FVD between building?

Dear all. We have used seismic attributes and Geostatistical inversion, but the result is not so good. The sand body is thin，we can not identify them using seismic data. So, we wonder know if any new method or other useful method we can try? Thanks all.

Hello fellow geoscietists,

I am currently doing my master thesis on a project, which tries establish a geothermal well for an industrial site in Germany.

Two 2D seismic lines have been created with vibroseis trucks. The quality of the data turned out to be very bad. There are barely any coherent reflectors and the whole profile of ~12km length and approximately 6000m depth is a giant chaos of many small reflector parts which do not show any geological patterns or formations.

I am working with PETREL, which does not offer any free tutorials and I am trying to intepret the two seismic lines, which I have to balance and reconstruct with MOVE later on. I am very frustrated with the data and am not able to produce much with it, since I could basiclly draw anything in this seismic profile.

Do you have any idea how to improve seismic data in this stage or how to handle this data in a thesis? I am supposed to offere several interpretations and reconstructions.

Seismic data are types of big data that are saved in .segy format. I am currently working on applying machine learning methods to 3D seismic data. I use the "

**Segyio**"**python**package to import and handle .segy files. The question I have here is**how to export a 3D NumPy array in a .segy file**with headers to save my results and import them into commercial software. Any help or sample code you can give me is greatly appreciated.