Nabajit, your question is interesting but I am afraid to say that it does not have easy linear answer. It is a known fact that land-forms witness sometimes major changes as a co-seismic response to big earthquakes. These earthquakes might trigger sometimes a potential avulsion. If a rupture has secondary effects in the form of higher order subsidences and upliftments, rivers carrying high sediment load might show newly defined sites of aggradation and degradation, relative widening and narrowing. On the other hand, if we put microseismic events during the interseismic periods of major earthquakes (that is, a gestation period), and short interval (temporal) monitoring of the satellite imageries are undertaken, suspected trends of tectonic controls can definitely be verified.

The first idea that probably comes to mind it that microseismicity might have an effect through mechanical forces. However, microseismicity is the result of stresses deep below and stresses have been shown to activate electronic charge carriers in rocks, which have the remarkable ability to flow out of the most stressed volume. They represent an electric current. Just like any other current, they can sustain their outflow only if there is a return current to close the electric circuit. Such a return current can be supplied through the electrolytical conductivity of water-saturated rock layers and all kinds of gouges in active faults. If so, electrocorrosion will lead to an accelerated dissolution of the rocks, which in turn will translate into variations of the "mineral" content (solute cation content) of the ground water that feeds into rivers. Have a look at:

Inan, S., W. P. Balderer, F. Leuenberger-West, H. Yakan, A. Uozvan, and F. T. Freund (2012), Springwater chemical anomalies prior to the Mw = 7.2 Van Earthquake (Turkey), Geochemical Journal,, 46, e11-e16,

and

Balk, M., M. Bose, Ertem Gözen, D. A. Rogoff, L. J. Rothschild, and F. T. Freund (2009), Oxidation of water to hydrogen peroxide at the rock–water interface due to stress-activated electric currents in rocks Earth Planet. Sci. Lett., 283(1-4), 87-92.

I think it is reflected in the river processes. Decades back I was involved in a project in India on a Department of science and technology project where we made a very close correlation with the meandering and sinuosity of the river Ghaghra (Ghandak) which showed a very mature stage with excessive meandering one if a very prominent geologist was suggesting structural control as a reason and with each earthquake event we were able to trace straightening of river and lots of ox now lakes were formed these sediments were dated and correlation was interesting unfortunately these were not published as a research paper but were in DST reports and I might find a copy if someone is interested.

@Siddhartha Lahiri : Thank you Sir for your reply. I think if I could meet you with my data that will be more fruitful to me as it is really difficult for me to interpret these findings without a solid knowledge of Geology.

@ Friedemann Freund: I think I have some more reading to do Sir before I could fully relate to your reply as with only a partial knowledge on the subject it is really difficult for me to understand the complex intricacies of the subject. :-)

but Thank you for your kind reply.

@Saif Uddin: A copy to me could be useful for sure. If you have one with you.

Nabaji will try to dig teh file am sure our Indian counterpart would have it and I should have a hard copy somewhere as those days we didnt had soft copies. Let me have a look at your area, if possible will try to interpret the way we did for that Project in India.

@ Richard Gloaguen: Thanks a lot Sir. I would look forward to Nils comments then.

Hi Nabajit,

We studied perhaps what is a novel type of impact of earthquakes on river processes, in our paper on subglacial seismic events and geothermal activity on the chemistry of a glacial river system in southern Iceland.

I’ll try and attach the Hydrological Processes paper below. Best wishes, Damian

Abstract:

The influence of subglacial geothermal activity on the hydrochemistry of the Jokulsa a Solheimasandi glacial meltwater river, south Iceland, is analysed. A radio echosounding and Global Positioning System survey of south-west Myrdalsjokull, the parent ice-cap of the valley glacier Solheimajokull, establishes the geometry and position of a subglacial caldera. A cauldron in the ice-cap surface at the basin head is also defined, signifying one location of geothermally driven ablation processes.

Background H2S concentrations for the Jokulsa meltwaters in summer 1989 show that leakage of geothermal fluids into the glacial drainage network takes place throughout the melt season. Chemical geothermometry (Na+/K+ ratio) applied to the bulk meltwaters tentatively suggests that the subglacial geothermal area is a high-temperature field with a reservoir temperature of =289-304 oC.

A major event of enhanced geothermal fluid injection was also detected. Against a background of an apparently warming geothermal reservoir, the event began on Julian day 205 (24 July) with a burst of subglacial seismic activity. Meltwater hydrochemical perturbations followed on day 209 and peaked on day 213, finally leading to a sudden and significant increase in flow on day 214. The hydrochemical excursions were characterized by strong peaks in meltwater H2S, SO:- and total carbonate concentrations, transient decreases in pH, small increases in Ca2+ and Mg2+ and sustained increases in electrical conductivity.

The event may relate to temporary invigoration of the subglacial convective hydrothermal circulation, seismic disturbance of patterns of groundwater flow and geothermal fluid recruitment to the subglacial drainage network, or a cyclic 'sweeping out' of the geothermal zone by the annual wave of descending groundwater. Time lags between seismic events and meltwater electrical conductivity responses suggest mean and maximum intraglacial throughflow velocities of 0.032-0.132 m/l, respectively, consistent with a distributed drainage system beneath Solheimajokull.

Because increases in flow follow hydrochemical perturbations, the potential exists to use meltwater hydrochemistry to forecast geothermally driven flood events in such environments.

Nabajit did you use some satellite datasets to map the drainage mutation over years in a river> Please see these changes appears intresting and if you have the seismic information, temporal integration will give you some meaningful results.

Hi Nabajit,

I think that our colleagues are right with their answers and hints. But allow a comment. Evolutionary natural systems move sometimes temporarily on saddle points in state space where they are unstable against small perturbations. Independent upon the nature of the perturbations they move the system either back to normal or into a novel direction in a multi-dimensional state space. What are the major forces? Mainly gravitation (water flows downhill), frictional forces, and inertia (the Earth rotates below the river...). What sorts of perturbations do we have in hydrology? First of all there are discharge, weather, and bedload fluctuations, variations in plant covers (root systems etc.) on the banks, seismicity, and, last but possibly not least, turbulent motions, large and smaller vortices and eddies. The question now is about the "force content" of these perturbations. It would be helpful if we have, say, an Excel sheet where in one column is the sort of perturbation including micro-seismics, and in the second column its "force content". This would be nice PhD theses! Regarding meandering of rivers, there is the Einstein theory (yes, the guy who did grativation and relativity) and you may find a lot in the books by my admired friend Selim Yalin. But all this you surely know since long and I stop now talking boringly redundant noise.

@ Damian Lawler: Thanks Sir. I have read your paper.

@Helmut Baumert: Every bit of information is important Sir. So thank you for your comments.:-)

@Damian lawler ,@ Helmut Baumert ,@ Richard Gloaguen and @ Siddhartha Lahiri: But my problem is still somewhat different as I want to see whether a particular trend of a river process is due to seismic activity or not? As I lack data regarding point events so an event based study of processes is not possible for me. Therefore I want to relate the trends that I am getting for migration, erosion and deposition in my rivers with micro seismic events.

@ Saif Uddin; I am trying exactly to do that but the integration part is bit confusing and difficult. :-)

This is true it is bit of speculation and loose ends. However if the temporal coverage is increased and you are able to get more images integration is likely but the amount of effort is too much.

Yes Richard is right some drainage morphometry will be helpful to relate it to tectonism and with each microseismic event the stress release should have some impact on the morphometry (direct or indirect).

Nabajit, let me assume that the river dynamics you are studying is located in the North bank of the upper reach of the Brahmaputra valley. As you are interested in correlating microseismic events with the river dynamics, you must have collected seismic data set say for the last twenty years or so from the NEIST, Jorhat. Assuming you have also collected satellite imageries( twenty/ten sets say, which might be a bit cost prohibitive but perhaps you have managed it) for different years. It is not difficult to isolate most change prone patches by measuring plano-temporal variations in the GIS based environment. Next, you may start drawing concentric circles around those patches and plot the epicenters of earthquakes having different magnitudes. Subsequently, you can go for a statistical correlation. But keep in mind certain other issues. The influence of the Himalayan Frontal Thrusts in the valley (in the form of blind faults, the leading edges etc.) are still not properly mapped (Both the OIL and ONGCL have done some work but published literature are very scarce). Secondly, many smaller faults are associated with some of the major faults. As most of the north bank tributaries of the Brahmaputra carry lots of sediments, the gradual migration of banks is a general sedimentology related issue. Thus, sedimentology plays a dampening effect on tectonic changes. Perhaps frequency filtering technique might help to separate these two things.

How precisely you can identify the epicenter when micro-seismic events are considered and particularly diffused seismicity.

@ Siddhartha Lahiri: Sir regarding sedimentology, is it possible to explore the migration and depositional causality using sedimentological study? Does it involves chemical characterization?

Except for powerfull ones that may change the landscape (landslides, huge collapses) and make it possible important modifications on the sedimentary processes or the creation of a natural dam, the effects of earthquake may be reduced and difficult to evaluate. A work is possible on long time periods. You need both good geomorphology and seismic analysis. The former to detect anomalies in the landscape (unaligned rivers, different elevations for alluvial terraces,...) and the latter to evaluate the activity of the faults. The problem is when you have non seismic fault movements.

It is related to geodynamics I believe there is a close relation between River Meandering and Earth Meandering, EM means earth twisting or earth dahwing(earth rolling). RM is fractal components of EM. I have new concept in global tectonics named as Spiraltectonics may help you fundamentally to  get the answer, in global scale I addresses the concave and convex shore of the earth. there is an abstract and one figure attached in researchgate. it may be helpful for you.