Geological Mapping - Science topic

All you need is here: PDS Geosciences Node https://pds-geosciences.wustl.edu/

Please take a look at the citation policy of GSI.

Very interesting rock. I think the large grains are oncoids because they developed on skeletal-fragment and intraclast nuclei and the coatings are not isopachous. The arrangement and size of the oncoids is interesting. The great range in sizes and the fact that they are "floating" in some kind of matrix makes me wonder if they have been resedimented. There are some broken oncoids but most seem to be intact so I wouldn't expect that this sediment was reworked by high energy currents. Is it possible that this is part of a small mass wasting deposit that formed by collapse of an intertidal channel? Thanks for getting my brain working. Have you found this site before? http://www.sepmstrata.org/page.aspx?pageid=211

Please find the attached map.

GSI Bhukosh website: https://bhukosh.gsi.gov.in/Bhukosh/Public

To expand on my previous reply, the accuracy standards for the lines drawn on USGS geologic maps are similar to those for the lines drawn on USGS topographic maps, as in the link that I sent earlier. Since the geologic maps are drawn on a topographic base, any errors in the topographic map will be transferred to the geologic map as well. These errors tend to be magnified by certain techniques. For instance, a map surveyed on the ground in the old days would tend to include details that might be lost in an aerial survey, because the ground crew worked under the trees and the aerial photos show only the tops of trees. In heavily wooded areas, the true elevations of deep valleys could be missed. With older maps, the accuracy standards may be different than for more modern ones. In particular, bear in mind that the older maps were literally drawn in pencil on sheets of paper. Even after digitization, these maps cannot be any more accurate than the width of a pencil line. And the digitization process does not add accuracy! Around 2000, I watched as GIS technicians clicked their mice along lines; the software added straight line segments between the points that they clicked on. When the points were clicked closer together, the accuracy was higher. Also, as I pointed out earlier, it is not possible to create a map that shows every small irregularity in the outcrop of a formation contact. The contacts will typically wander up the valleys and down the ridges, and in an area of low relief, this means that the contact may zigzag considerably. The authors of a map must decide how much of this wandering is significant. When I worked for the Geological Survey of Alabama, whose standards are based on those of the US Geological Survey, I was told to ignore thicknesses of less than 8 feet while working on the low-relief Coastal Plain, where outcrops are few and scattered, soil and vegetation obscure the contacts, and soils and rooting are sufficiently deep to make recognition of different formations difficult without time-consuming excavation. At the scale we were working at, the extra time was not worth the effort. The real contact would be a fractal curve! So, to sum up, there are systematic errors related to problems of scale.

DEAR GIUSEPPE

GOOD AFTERNOON. THE WEBSITE WITH THE GEOLOGICAL MAP OF SAN MARINO IS https://mappeonline.pa.sm/maps/geologica_vis/

I ALSO SEND YOU ATTACHED A PDF ON THE GEOLOGY OF SAN MARINO. FINALLY, YOU CAN FIND A RELATED BOOK ENTITLED "Atlante delle formazioni geologiche della Repubblica di San Marino" WITH ONLY 22 EUROS.

BEST REGARDS

IOANNIS

First, create an empty polygon layer with the same coordinate system as the initial layer. Now create the layer according to your desire with the editor tool.

Dear Jorge,

I think you are looking for defined grid patterns for mapping.

But I would like to tell you about a special mapping.

I had to mappe an area of 1500 square kilometers at a scale of 1:5000 according to sedimentary petrographic criteria for a drinking-water risk analysis project.

Geologically, it was the Upper Freshwatermolasse of Bavaria, a neogene system of rapidly changing deposits of braided river- with meandering river-systems and partial overburden of quaternary loess and alluvial-filled depressions.

I had to map the sediments as they come.

In some areas even a narrow grid of e.g. 50 m could have distorted the result, in others a 100 m grid would be sufficent.

I should mention that the area is used for wells for municipal drinking water supply and therefore the data should be as accurate as possible for further processing.

Many greetings,

Wolfgang

Let me check with the Geol Surv Pakistan. But only for support, not authorship.

Pl send me your email. Mine is <mqjan@yahoo.com>

Dear Pierre

hi

did you get the maps you needed

Naser

Remote sensing images are used for mineral exploration in two applications: (1) map geology and the faults and fractures that localize ore deposits; (2) recognize hydrothermally altered rocks by their spectral signatures. Remote sensing in geology is remote sensing used in the geological sciences as a data acquisition method complementary to field observation, because it allows mapping of geological characteristics of regions without physical contact with the areas being explored. Remote sensing is a valuable tool in mineral exploration, thanks to its ability to save time and money while providing helpful information. It is best used for the discovery of high-value commodities such as diamonds and gold, which are becoming more difficult to locate.

Also this paper will help you:

Dear Aamir,

Better go to the National Centre of Excellence in Geology library. If they do not have, request the Geological Survey of Pakistan (GSP) office in Peshawar. If I remember correctly, at least a part of the quadrangle was remapped by Professor Sajjad Ahmad, now Director General GSP.

That is a good question.

Hello dear;

I didn't research on Paleomagnetic studies, but i know 2 methods in order to behavioral study between two things. K-means clustering and Artificial Neural Network (ANN). you can read this combination method in this paper :

good luck

Thank you Karl-Jan Erstad but that was certainly my first guess. I was hoping that someone could point me to an "un-google-able" source or better yet, they have it up their sleeve.

If you are working in India, then go for GSI online maps of geology. https://bhukosh.gsi.gov.in/Bhukosh/Public

QGIS

Saga GIS

Surfer by Golden Software is my favorite, https://www.goldensoftware.com/products/surfer.

In addition to having all the map-drawing tools, it links to numerous data repositories, and its support is unmatched in the industry.

Udara Hasantha Piyathilake There is no need to convert your image into Kmz. The Google Earth Pro entertains wide variety of image file formats. Just open your image directly into GEP. Doing so, the native image quality is retained.

Once you open the image and set destination path, a dialogue box may prompt you allowing to choose available option. Just press 'Scale' to view the whole image to maximum supported size.

Hello Jaime,

At least several fragments in the three images correspond to radiolitid rudists (Bivalvia, order Hippuritida, family Radiolitidae). The celluloprismatic structure of the outer shell layer (you can see it in the fragments), is currently considered a main diagnostic feature of the Radiolitidae.

Saludos!

https://support.esri.com/en/technical-article/000019199

Henrique Joncew,

It is true that geophysics is a tool, but it has specific and general tasks that cannot be solved by conventional geological methods.

Geophysics allows, in conjunction with geology, to solve numerous aspects in geological mapping. For example, conventional geological methods can only explain what is seen directly by the surface geologist. In its aid, geophysics makes it possible to propose geological features that cannot be seen with the naked eye: geological strata and bodies at certain depths; presence of the water table; presence of contacts or faults that do not emerge, etc.

The advantage of aerogeophysics is given by its speed and the possibility of covering large areas where, at times, it is unlikely to develop land campaigns. The rapid development of remote sensors has come to the aid of Geosciences and their combination with aerogeophysics, undoubtedly, allows solving tasks that just a few years ago would be unlikely.

In Cuba there is a 1: 50,000 aerogeophysical survey of the entire territory and certain areas at a scale of 1: 25,000. So, the idea of ​​the question is to exchange experiences with colleagues in other latitudes and thus improve our results.

Thank you very much for your help,

Multispectral imaging and thematic mapping allows researchers to collect reflection data and absorption properties of soils, rock, and vegetation. This data could be utilized by trained photogeologists to interpret surface lithologies, identify clays, oxides, and soil types from satellite imagery.

ASTER (15m) Satellite Images

Hallo, I would like to know better lithological-stratigraphic characteristics and local karst. The area is name BZYB. I have found some informations yet, like the map in attach, it is interesting

use this paper for more

Significance of saturation index of certain clay minerals in shallow coastal groundwater, in and around Kalpakkam, Tamil Nadu, India

I'd be careful when using Google Earth to analyze temporarily varying things like landslides. The Google Earth cloud free image is stitched together from different scenes at different times. While it should be no problem mapping slowly evolving features such as faults, for landslide mapping this could become an issue.

Dear all: Yes, geology was done in the field when no satellite imagery was available many decades ago. I belong also to the "pre-digital" era, since I entered the Geology Department ar C.U.V. in 1976. In my country, Venezuela, when I was a student and in the beginning years of my career, many places didn't even had topographic maps in low scales, and some still haven't! Most of these remote places were accessible only through creeks and rivers, no roads whatsoever, not even dirt roads! All one had were 1:100.000 or larger scale maps of part of the territory. So one had to "draw" the creeks and rivers using topographic equipment, beginning with some reference point, usually a church bell-house in small towns. And then put the lithologic contacts, structures and the like on the newly drawn map!

I don't agree when somebody says that field mapping was perfect, or 100% perfect. There is nothing perfect in geology, to say so is to be really naive ir extremely optimistic! No matter how good outcrops one might find, no matter how well the sampling is done, no matter how sophisticated equipment is used for chemical, isotope, and radioactive analysis, we never will be able to describe 100% of the geological events happened in the past. It is simply impossible! We can give educated propositions of geological history, but not the 100% of the facts. Let's be a bit modest, right?

Moreover, a great part of geological history has been erased by that villain called erosion, so no continuous sequences exist anywhere. It is like a CSI crime scene where some intruder takes away valuable evidence from the site! In tropical countries mapping is very defective, since thick lateritic soils, heavy forests, and wide alluvial deposits cover most of the terrain. In mountainous areas all one can have is outcrops in creeks and rivers, and many of them are quite difficult for access, as they have falls, cataracts, rapids, and all sort of obstacles. Even road outcrops get quickly weathered and become useless after a few years! But, as I said before, and I always remind to my students at the beginning of each semester: even in the best outcrops you might find in Greenland, Canada, Siberia, and desertic areas, more than 70% of the geological history has been erased by the erosion villain! Regards, Sebastian.

Dear Damilola Avioye:

Even though, there is a need for studies to estimate the Curie´s temperature from aeromagnetic data, I would like to comment why this approach is faulty and the use of the magnetic data is inappropriate if you are trying “calculate curie temperature of each rock from magnetic anomalies” such as you said. My observation first addresses the data use in this study-case reading the geological and geophysical background (1), then ideas how the analysis was performed (limitations) (2) and finally presents an scenario of numerical examples (3) to illustrate the limited and misleading results that could be generated.

1) Following Raimi,J., Dewu, B.B.M. and Sule, P. (2014) An Interpretation of Structures from the Aeromagnetic Field over a Region in the Nigerian Younger Granite Province. International Journal of Geosciences, 5, 313 - 323. http://dx.doi.org/10.4236/ijg.2014.53031, your study area is largely covered by basement rocks and ring complexes Ririwai, Gamawa aand Zuku, Banke, Ningi and Tibchi-Yeli outcrop in the area. There is a high resolution aeromagnetic data by tne Nigerian Geological Survey Agency (NGSA) were acquired at a flight altitude of 80 m, along NE-SW flight lines that were spaced at 500 m. The authors, used the Euler deconvolution to estimate the depth and position of the main structural features explain: “The results of the Euler solutions indicate that the depth of the ring complexes range from outcrop to 1800 m. For the inferred unexposed ring complex, the depth range from outcrop to 1200 m. It also revealed tightest cluster of solutions along inferred folds with depth that range from 0 to 1800 m.”

2) On the other hand: Curie point depth is a theoretical surface with a temperature in order of 550 °C / 580 °C and can be considered an index of the bottom of a magnetic source, due to ferromagnetic minerals converting to paramagnetic minerals. Geomagnetic anomalies, which are retrieved from magnetic survey, can be utilized to study magnetic structures above the Curie point depth (Bhattacharyya and Leu, 1975; Byerly and Stolt, 1977; Blakely and Hassanzadeh, 1981; Blakely, 1988; Smith and Braile, 1994; Tanaka et al., 1999; Chiozzi et al., 2005; Eppelbaum and Pilchin, 2006; Trifonova et al., 2009; Aboud et al., 2011). On the other hand: you need to reduce the influence of boundary conditions and edge effects, avoid the high frequency noise caused by structures near the surface, and the spectral analysis of the magnetic data described by Spector and Grant (1970) estimated the depth to the top of magnetized rectangular prisms (Zt) from the slope of the log power spectrum, and using this spectral method, Bhattacharyya and Leu (1975, 1977) further calculated the depth of the centroid of the magnetic source bodies (Z0). Okubo et al. (1985) developed the method to estimate the bottom depth of the magnetic bodies (Zb). From the slope of the power spectrum, the upper bound and the centroid of a magnetic body can be estimated. The lower bound of the magnetic source can be derived (Okubo et al., 1985; Tanaka et al., 1999) as Zb = 2Z0 - Zt.

Since Zb is the lower bound depth of the magnetic body, it suggests that ferromagnetic minerals are converted to paramagnetic minerals due to temperature of approximately 580 C. Therefore, the obtained bottom depth of the magnetic source, Zb, was

assumed to be the Curie point depth. To relate the Curie point depth (Zb) to Curie point temperature (580 C), the vertical direction of temperature variation and the constant thermal gradient were assumed. The geothermal gradient (dT/dz) between the Earth’s surface and the Curie point depth (Zb) can be defined by Eq. (8) (Tanaka et al., 1999; Stampolidis et al., 2005; Maden, 2010): dT/dz = 580 °C/Zb.

Another critical issue is the size of your ZOI that you need to use as input in the Curie´s temperature from magnetics: the depth simulations suggest that the optimal square window dimension is about 10 times the estimated depth. For example, you must take square subregions of 200 km by 200 km; or 250 km by 250 km, in a shifting increments of 10 km respect to each other.

The lasted idea to say to you is the vertical resolution of this geophysical method: it is in order of hundred meters, also, it is almost impossible to “calculate curie temperature of each rock from magnetic anomalies” (Please, see the textual comment by Professor Alan Reid at bottom) such as you said.

3) In synthesis: If the results of the Euler deconvolution cited by Raimi,J., Dewu, B.B.M. and Sule, P. (2014) are correct, it is almost impossible to reach the Curie´s critical temperature at this shallow source and the size of your magnetic survey relationship. Thinking if you are in a region of shallow Curie Point Depth such as 10 km, it means that there is a high geothermal gradient, e.g., 60 °C/km and present heat-flow value (200 mW/m2!!!). Is your geological – scenario like this?

"...It is important to understand that the spectral methods are great in the right hands, but you´d better read prudently the Spector and Grant foundational paper (1970). Remember they give averages over the spectral window, and you need to beware of the Power spectrum calculated this way. The one you get with RAPS has a lot of its power from the grid tapering outside the data (to make the edges match), so it´s biased. You need to calculate the power spectrum yourself with internal tapering to get edge matching and no grid extension outside the data". (Alan B. Reid, 2015).

Best regards,

Mario E. Sigismondi

Dear László and colleagues:

It is not an easy answer your doubt, even more: it is my doubt too. Keep in mind that certain of plate boundaries are not defined so simple than others by earthquakes, such as the South America – Nazca – Antarctica example that I made to Jeffrey´s original question.

To try to answer the László´s question, "What is the Lithosphere thickness in ‘subduction zones’ of Mediterranean?" I researched using satellite data from Gravity Recovery and Climate Experiment (GRACE) and I got an estimate of the Crust – Upper Mantle boundary. Also, I use the earthquakes database from the USGS to map the main earthquakes between the period 1919 – 2019.

Please, allow me to share with you and colleagues four images of the results obtained, in the PDF file attached in this answer: 1- gravity anomaly; 2- Moho depth; 3- earthquake depth and 4- earthquake magnitude.

If you have a specific database of Europe region in mind it might be worth looking up these data. It’s also worth noting that I will help you to understand better your question. This means your focus should be on getting quality gravity and, also, magnetic data, I will do my best job.

Best regards

Mario E. Sigismondi

The geological map shows the distribution of the formations and their contact ( different kinds of rocks and faults).

There are three major types of maps they use: topographic, cross-sectional, and structural.

A structural map shows the geologic features of an area. Its appearance is similar to that of a topographic map, but a topographic map displays elevations of the Earth's surface and a structure map displays the elevation of a particular rock layer, generally beneath the surface. a geologic map shows the distribution of geologic features, including different kinds of rocks and faults.Rock units or geologic strata are shown by color or symbols to indicate where they are exposed at the surface. Isopach maps detail the variations in thickness of stratigraphic units.

A cross-sectional map shows the cross-section from the side.

So you can't talk about stratigraphic maps, but rather structural maps at different stratigraphic levels,

I am the head project and there is not any map for the area by the Egyptian geological Survey, I have been collected the samples only without any person. I only made a geological map for area. I will no give any other, I have got fake paper and PH.D.

First of all, they must be able to extract water for their salt water metabolism, that is, filter the salt and harmful elements, and they must also be able to resist UV radiation, which is high in these ecosystems.

Any one who can share me a book on tropical environment ?

thanks

Anderson's Theory assumes one of the principal stress axes to be vertical as the earth's surface (i.e. air) has no shear stress (like every fluid). Only normal stress is acting. Thus, the theory is only applicable at the earth's surface, not in deeper parts of the crust (where shear stress increases).

Forward modelling is well suited to iterative modelling and testing of geological concepts. You learn a lot about the sensitivity of different free parameters. For complex models, inversion is your assistant to reduce the time it takes to get the best solution for a given set of free parameters.

I work on the principle that the smallest number of free parameters that will satisfy the data and your constraints is the best point to stop.

If your match is still not good, then you need to explore the underlying geological assumptions and constraints such as those suggested by Leon. This is a general response to a broad range of geological problems that needs to refined for specific geological styles. For example, mineral exploration models and seismic section work flows are very different.

To All who provided answers and insight to my question above: thank you. Your suggestions are entirely sensible and valid, and clearly come from good knowledge of relevant disciplines, and from experience. I apologise for my delay in replying. Our concern at the time was the seemingly random recommendations and 'geophysical survey' results we had received. But then we discovered a company who had previously drilled several boreholes in the area without success. Even though I suspect they did not use any advanced techniques to identify the locations, this did not bode well for our project, which had enough for a single drilling effort only. But the village in question does have access to a surface waterhole in a shallow ground depression, so I think this was the most obvious way to address their water security needs - even though it needs treatment. Many thanks again - I just thought I would give you feedback on how it turned out. Kind regards.

Dear Nisarg,

Although I've never used TecDEM, I've calculated the steepness index manually by extracting area and slope data using ArcGIS. I wrote the entire technique in my recent paper, published in Arabian J Geosciences.

In case, if you want to compare steepness index of many streams, you've to normalize the steepness values using a reference concavity. To easily compute the normalized steepness index you may follow the stream profiler tool and the MATLAB codes developed by Kelin Whipple and his team.

Cheers.

Sumit

Wow, many thanks ! Indeed a piece of sweet cake for my project (Mariana Trench, Pacific Ocean).

Avijit:

Have a look at this map:

Best

Syed

can use this

Dear Sir

I think the links below will benefit you in your search

Best Regards

Thanks James Varghese,

I eventually got a coouple sentences out to Sameera, and presently attempting to send a partial text to him and another person, soon.

Jeff Spence

7/5/18

Please have a look at enclosed PDF...

According to Buday's (1980) Oligocene Facies Distribution Map(Page 289 in the Regional Geology of Iraq Volume 1), the Oligocene rocks either eroded or not deposited in Duhok area.

Please see the attached map.

I am not sure, what type of subsurface data you want to correlate with remote sensing techniques. However there are various proxies that can be used to correlate elevation, terrain classes, geology to the surface information. But these are not global correlation, for example, you have to first see if any such correlation is available for local conditions, then you may use , but in absence of that, you have to develop correlation for DEM, elevation, geology with subsurface data (for few sample measurements), then you may apply that correlation to overall local ground.

I did not say that they would all be placed the same!!!!! The idea is to gauge how much lithological change occurs within a determined distance and then base your grid on that.

The above answers involve trigonometry. To show a non-geologist, try drawing a cross-section. To do that you need topographic contours and a bedding dip reading. It is not rocket science, nor does it require mathematics. In some areas you could assume that the topography is flat (or approximately flat).

I think I have some maps around Khaleej Sirte

Thanks Meryem.

I think these maps will be available from the GSI. YOU CAN COPY THE MAPS AND THEN SUPERIMPOSE THE uttrakhand boundaries. Soil.maps avaible from Soil Department.

You can plot your data on stereonets and rose-diagrams for each location or any other way that fits your purpose. You can use any of the many programs that you can find online (some have already been suggested) to create your diagrams. Then you can add the diagrams on your map. Alternatively or additionally you can use the appropriate geological symbol and plot your structures (or the average orientation) on your map directly. See this for an example: https://www.researchgate.net/publication/322438484_Contribution_of_geological_mapping_in_road_construction_an_example_from_Veria_Kozani_national_road_Kastania_area

The interpretation of your data is a more complex task and it depends on the purpose of your investigation, the knowledge of the regional geology, the quality of your data etc.

Regards

George

I don't have much knowledge about that algorithm but it mainly works for the edge or boundary detection in the mineralized region.

through this you get some help but it is not done by using ENVI software.

1. Revision of the scale of last North American glaciation Part 1. Southern Rocky Mountains

2. The origin of lakes and sandy deserts of mountains during the melting of glaciers –Taklamakan and Gobi deserts (EN)

Dear Dr. Leonardi,

even if you could only provide us with a limited insight into the surface phenonmena of these sandstones I would discard the idea of being biogenic in origin and I would rather attribute this kind of sandstone structures to what might be called sensu lato as parting (lineation). It is not uncommon at outcrop and when used as glading it shows this man-made way of exfoliation. You might find these structures in some otherwise monotonous arenaceous series such as those created by turbidite currents.

With kind regards

H.G.Dill

u may try downloading from following link:

I believe that EM-I end-member is strongly influenced by the recycling of ancient lower continental crust. On the other hand, EM-II end-member is more likely associated to recycling of subducted sediments.

See attached some articles of mine dealing with this argument.

Cheers,

michele

friction

GPS isn’t good technique for geodetic monitoring of structures, like dams or bridges due GPS low accuracy, shadow zones or dead areas in the satellite observation of structures.

I don't prefer to use such technology for this aim unless we improve the GPS accuracy.

Please check the attached files.

Very interesting topic

Here you can find several tools to assess rockfall hazard: http://www.ecorisq.org/ecorisq-tools. For an accurate mapping it is better to use Rockyfor3D but it demands some field works.

As said before you can also use RAAMS.

Tomasz,

Two references that would be useful are those of Lew Ashwal (1993 and 2010) on anorthosites generally. The AMCG complexes are mostly of the Proterozoic massif-type variety of anorthosites, I believe.

Ashwal L R, 1993, Anorthosites. Springer-Verlag, Berlin, Germany.

Ashwal L R, 2010, Canadian Mineralogist V48, P711-48. DOI: 10.3749/canmin.48.4.711

The book would have maps and locations, the later article on temporality of anorthosites has an updated list of massif-type anorthosites with all the major occurrences and their broad locality (country/region/state).

Dave

Dear Mr. Adeoti,

I am currently studying basement rocks rife with pegmatites and aplites. I would like to re-direct your thoughts to the classical field work combined with a meticulous analysis  of your planar and linear architectural elements using the stereographic projections (stereonet diagrams) for interpretation. Before making use of a lot of papers and trying to find everything there in your study area too, I recommend some good textbooks on structural geology for field and laboratory work, unless you are a trained structural geologist.

A wealth of  information how to come to tackle this kinematic issues is published in the books of Van der Pluijm & Marshak (2004), Fossen (2010),  Lisle et al. (2011) and Davis (2013).

Good luck

Harald G. Dill

thank you sir

The history of the term "Quaternary" is well explained above by Mr. Dill. So in an old way of earth creation classification, Quaternary was the fourth phase, and maybe the etymology is from Italian language "Quarto".

Arduino was firs to use it, when studying the geological cross section of north Italia observed four kind of rocks, which began from ultramaffic rocks (primary) to recent unconsolidated depositions (fourth or quarto).

The acceptance of this concept was very difficult, but at the end the Quaternary is the only therm survived by the fourth class classification.

Today is accepted than Quaternary begin 2.6 million years before now, and is subdivided into Pleistocene -2.6Ma to 11.7 ka, and Holocene from 11.7Ka until present.

The main characteristic is the appearance of Homo Sapiens during this geological Period and the glacial inter-glacial oscillation during Pleistocene (four significant).

Quaternary deposition are deposition that belong to this period, younger of which belong to Holocene. Quaternary landslides is a therm that I encounter for the first time, but I believe they are actual and active landslides and that this must be the correct terminology. I don't believe a landslide can be collected with an entire geological period, as we can do it with tectonic activity.

But it must be in the concrete framework. if they are some landslides, created by sea level rise during the Holocene transgression, you can use a term like Holocene landslides, but the correctness of this term is to be evaluated.

 

 

 This reference may be of interest for you: Iwasaki T.,Tokida K.,TatsuokaF., Watanabe S., Yasuda S., Sato H. (1982)Microzonation for soil liquefaction potential using simplified methods. In: Proceedings of the 3rd International Conference on microzonation, Seattle 3: 1310–1330.

Na Li 您好

I am working in North eastern Himalaya-Siang Valley but the research is on Foreland basin not the Himalaya.. although I will try my best to help you. Please let me know 

Here are some links to refer , please:

LDAS | Land Data Assimilation Systems - GLDAS Soils

Mar 16, 2017 · The basic soils information used in GLDAS was derived from the global soils ... on the FAO Soil Map of the World linked to a ... Soil Porosity.

A glimpse beneath earth's surface: GLobal HYdrogeology MaPS ...

www.researchgate.net/publication/262387804_A...

Official Full-Text Paper (PDF): A glimpse beneath earth's surface: GLobal HYdrogeology MaPS (GLHYMPS) of permeability and porosity

SOIL STRUCTURE, DENSITY AND POROSITY

SOIL STRUCTURE, DENSITY AND POROSITY Ifthe mixture ofsand, siltand clay ... soil and increasing the porosity of the soil, particularly the macro porosity..

Dear Robin …….we applied many equations to estimate the Crustal thickness of the Earth in Iraq using Bouguer gravity values. These equations and our obtained equation were summarized in table one in our paper entitled "Crustal thickness map of Iraq deduced from gravity data", that published at 1994.....some of these equations are  T(km)= 33- 0.055 g(mgal) (Worzel and Shurbet 1955), T(km)= 32- 0.08g (mgal)(Woollard 1959)  . A Crustal modeling that depends upon Seismological data was used to constrain the gravity models. We hope you will success to achieve your study…good luck. Prof. Ahmed S. Al-Banna

Simply save the GoogleTM Earth images as KMZ. Then import them to Global mapper.

 Then export them to shape file to Arc Gis. 

 Run Geometric calculate. you will find satisfy answer. 

I was about to say USGS  portal but James Varghese has already mentioned that. 

yes, sure.