Identifying plausible historical scenarios for coupled lake level and seismicity rate changes: The case for the Dead Sea during the last two millennia

Belferman, Mariana; Agnon, Amotz; Katsman, Regina; Ben-Avraham, Zvi

doi:https://doi.org/10.5194/nhess-2021-62

Preprints

https://doi.org/10.5194/nhess-2021-62

Preprints

24 Mar 2021

Review status: this preprint is currently under review for the journal NHESS.

Identifying plausible historical scenarios for coupled lake level and seismicity rate changes: The case for the Dead Sea during the last two millennia

Mariana Belferman¹, Amotz Agnon², Regina Katsman¹, and Zvi Ben-Avraham¹ Mariana Belferman et al.

Show author details

¹The Dr. Moses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3498838, Israel
²The Fredy & Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel

Received: 26 Feb 2021 – Accepted for review: 20 Mar 2021 – Discussion started: 24 Mar 2021

Abstract. Seismicity triggered by water level changes in reservoirs and lakes is usually studied from well-documented contemporary records. Can such triggering be explored on a historical time scale when the data gathered on water level fluctuations in historic lakes and the earthquake catalogs suffer from severe uncertainties? These uncertainties stem from the different nature of the data gathered, methods, and their resolution. In this article, we considerably improve the correlation between the continuous record of historic water level reconstructions at the Dead Sea and discrete seismicity patterns in the area over the period of the past two millennia. Constricted by the data from previous studies, we generate an ensemble of random water level curves and choose that curve that best correlates with the historical records of seismic stress release in the Dead Sea reflected in the destruction in Jerusalem. We then numerically simulate a synthetic earthquake catalog using this curve. The earthquakes of this synthetic catalog show an impressing agreement with historic earthquake records from the field. We demonstrate for the first time that water level changes correlate well with the observed recurrence interval record of historic earthquakes.

Mariana Belferman et al.

Status: open (until 07 May 2021)

Post a comment Subscribe to comment alert

RC1:
'Comment on nhess-2021-62', Anonymous Referee #1, 30 Mar 2021 reply
In this paper, the authors apply a constant tectonic shear loading on a theoretical 1D vertical strike sip fault along with water lake forcing at the surface and calculate nucleation of seismic events. They use different water level history curves and choose the best fit water level that predict synthetic seismicity similar to historical records. They conclude that based on the similarities between their synthetic seismicity and the historical seismicity they can constrain water level history of the Dead Sea – Lisan lake.

I find this work to be misleading for several reasons:

There is no obvious correlation between lake level and seismicity. Seismicity occurs equally at high and low levels (Fig. 1 c and d). If at all, the water level has a minor effect on seismicity. The major forcing for seismicity is tectonic forcing. The reason that earthquakes do show exact intervals of recurrence could be related to changing shear forcing, damage processes, or viscoelastic relaxation. In my opinion, these processes are more likely to be responsible for the changing recurrence intervals. It is possible to get non-uniform intervals with any diffusion process and lake loading and pore pressure diffusion seems to me to be the least favorable. Furthermore, the model used in this paper use very questionable assumption (see following sections).

The most questionable assumption is that the pore pressure at hypocentral depth approaches the value at the lake’s bed. At the Dead Sea, even shallow boreholes are over pressurized. Water level in Ein Feshkha are artesian. Shallow aquifers <30m do not approach the lake water level. Ein Feshkha site is very close to a fault. Hypocentral depth at the Dead Sea could be 25 km. Between seismic events, faults heal and the permeability of the faults is very low. Deep layers will never approaches the value at the lake’s bed. Given a reasonable permeability, it will take millions of years. How can pore pressure at this depth approach the lake pressure? What about compaction and poroelastic loading? Furthermore, the diffusion time depend on the hypocentral depth. Hypocentral depth could be any number between 1 and 30 km. This will have a great effect on the relaxation time. The model does not take this into account because the hypocentral depth are unknown.

A second questionable assumption is that the pore pressure throughout the Dead Sea Basin at any depth responds elastically to changes in the lake level. The Dead Sea basin is layered with different rocks and soils. In fact, most of the basin is made up of clay. Clay is very plastic. Any deformation at the surface will plastically deform the clay and will not affect deep layers. The loading efficiency is very low. The rate of the water level changes is much slower than the rate required for plastic flow in the clay to redistribute deformation. I estimate that changes of 25m in water level loading at the surface do not significantly affect the stress at depths below 2-3 km.

To summarize, in my opinion, there are many problems with the simplistic model suggested in this paper. It ignores many processes and use unreasonable assumptions. This model cannot be used to calibrate the water level history of the Dead Sea.

Reply
Citation: https://doi.org/10.5194/nhess-2021-62-RC1
- AC1: 'Reply on RC1', Mariana Belferman, 20 Apr 2021 reply
  
  With gratitude for the reviewer’s interest in our article, we draw attention to a few points regarding his comments:
  Comment 1:
  - According to the reviewer, the correlation between water level and seismic activity at the Dead Sea Basin is insignificant (our Fig.1).
  Response:
  Our earlier work demonstrated a correlation between water level and the recurrence interval of Dead Sea earthquakes (Belferman et al., 2018, Fig. 9). The present study (Figure 2 and corresponding text – pp. 13, lines 236-237 and Eq.7) indicates that the correlation between seismicity and water level change might even be higher than that demonstrated in Belferman et al., 2018 (Fig. 9). We explain that significant uncertainties in the water level data-set might hide the correlation (please see pp.3 50-71).
  
  - Seismicity occurs equally at high and low levels (the reviewer refers us to Fig. 1 c and d)
  Response:
  Our model does not preclude seismic activity during water level drops, it just takes longer for the loading to reach the increased threshold. We even predict the next future earthquake, when levels are projected to reach an unprecedented low. The reviewer writes about the correlation between the water level and seismic activity; please note - Fig.2c,d shows that the change in level inversely correlates with the recurrence interval of earthquakes, rather than with "seismic activity". In the submitted paper the linear correlation is clearly visible in the figures, especially in figure 1c. The Pearson correlation coefficient reported in detail should make this point clear.
  
  - According to the reviewer, all change in seismic activity is due to changes in the tectonic loading and the state of the solid crust. By his assessment, the water level change has a minor effect.
  Response:
  Tectonic motion is the primary cause and consequence of earthquakes in our model as well, but it is worth considering other factors triggering earthquakes. We refer the reviewer to our Introduction section: water level induced seismicity in particular, and anthropogenically induced seismicity in general, are broadly recognized phenomena over the world.
  The seismic response has been observed to be connected to reservoir impoundments and their seasonal water level variations (Gupta, 1992; Talwani, 1997; Tomic et al., 2009; Hua et al., 2013).
  Davies et al. (2013) compiled 198 examples of anthropogenically induced seismicity since 1929 all over the world, where higher magnitude earthquakes within this list (up to 7.9, in Zipingpu reservoir area, China 2006) are most often associated with reservoir impoundment. Foulger et al. (2018) presented a comprehensive and up-to-date database of seismicity induced or potentially induced by anthropogenic sources.
  van der Elst et al. 2016 show that the appearance of induced seismicity requires a reconsideration of seismic hazards, even in regions of formerly negligible seismic concern. Simpson et al. 2018 & Gupta 2018 indicate many statistical studies that reaffirm this correlation.
  In our previous work (Belferman et al., 2018), we indicated that this phenomenon may even be more applicable to the historic lakes, like those occupying the tectonic depression of the Dead Sea, due to the larger scale of water level fluctuations. The post-diffusion stage (when pore pressure at all depth approaches the value at the lake bed), is relevant for early historical data. At this stage, an increase in pore pressure due to the water level rise always dominates over the loading effect, leading to varying but always negative normal effective horizontal stress change at any combination of poroelastic constants (please see Belferman et al., 2018 Fig. 5b). This should trigger earthquakes with magnitudes higher than those in the corresponding immediate undrained (rapid) response, coming shortly after the corresponding water level rise (confirmed, for instance, for Lake Mead, Gupta, 2002; Simpson et al., 1988; Monticello reservoir, Rajendran and Talwani, 1992, and others).
  
  Comment 2:
  - The reviewer doubts the assumption that the effective normal vertical stress vanishes, and argues that given a reasonable permeability, it will take millions of years. In particular, he argues that between seismic events, faults heal and the permeability of the faults is very low. He chose the Ein-Feshkha spring, very close to an exposed fault, to argue for a lack of hydraulic connection with the deep aquifers.
  Response:
  Some of the material characteristics in fault zones may vary significantly, depending on the types of host rock and on state variables (e.g. temperature, pore pressure, depth, etc.). Specifically, values of hydraulic diffusivity of intact rocks differ considerably among rock types (Rice and Cleary, 1976), and strongly decay with depth (e.g. by ~6 orders of magnitude at a depth of 20 km compared to the shallow crustal values (Ingebritsen and Manning, 2010). However, such laboratory values are not determined under conditions approaching hydrofracture. Pore pressure diffusion in fault zones is usually dominated by fault damage zones, which act as conduits (Simpson et al., 1988). The reviewer mentions damage processes as a possible determinant of seismicity fluctuations. We totally agree and refer to Hamiel et al. (2005) where we simulated how, under damage accumulation, slender porous zones evolve and become faults. Recently, a poroelastic analysis by Jim Rice’s group of a real case of induced seismicity considered a realistic damage/permeability structure with a fault core and anisotropic damage/permeability zones. They have shown that the permeable zones indeed propagate from shallow depths to the seismogenic zone with hydraulic fracture (Yehya et al., 2018). In fact, a useful illustration of a related phenomenon was given by Yechieli and Bein (2002), preceding the largest instrumental earthquake on the Dead Sea Transform - the 1995 Gulf of Aqaba M7.2 event some 200 km away.
  Hydraulic diffusivity around faults, as obtained from various seismological observations, is independent of earthquake hypocentral depth and estimated to be on the order of 5.0 m2/s, termed as “seismogenic diffusivity” (e.g. Talwani and Acree, 1985; Hua et al., 2013; Talwani, 1997; 2007). This suggests that the flow through faults is relatively independent of the rock type (see Ingebritsen and Manning, 2010, and references therein). Therefore, the diffusivity of faulted rock in our study is best represented by the typical value of high-porosity Boise sandstone, 4.0 m2/s (Wang, 2000), as used for our calculations.
  Using this diffusivity, we calculate the diffusion time scale, that indicates the time of arrival of the excess pore pressure from the lake's bed to hypocentral depths over the fault, for an average hypocentral depth underneath the Dead Sea fault system, z ≅ 20 km (Aldersons et al., 2003; Godey et al., 2006; Shamir, 2006). This time scale is ~3yr, according to the characteristic time scale definition (e.g. Kirby, 2010; Wang, 2000). For more details see Belferman et all., 2018, Eq.3 and explanation below.
  This time scale is negligible compared to the typical recurrence intervals of decades and longer of moderate-to-large earthquakes (M > 5.5) in the Dead Sea area during the studied period (see Tables A1, A2, and text in Appendix chapter in the current ms). It is also insignificant compared to the minimal temporal uncertainty in the lake level curve, nominally taken as 10 years in our simulations.
  Regarding the Artesian aquifers around Ein Feshkha - these are very local, minimal (two out of numerous boreholes), shallow, and ephemeral (Swaed et al., Geological Survey Report: GSI-10-2014). Their relationships to faults are poorly established, as is the historical activity of the nearby fault (Sharon, et al., 2020). More relevant are the thermal waters, ubiquitous in the basin. These require connectivity within the top kilometers of the section.
  - The reviewer notes that even shallow boreholes at the Dead Sea are over-pressurized. Following this, he rules out vanishing of the normal vertical effective stress.
  Response:
  Our response concerns two points, mechanical and hydrological. The manuscript explicitly treats the effect of water level change relative to its minimal level (415 m below mean sea level - bmsl) over the period studied (pp. 8, rows 157-160). The normal stress change generated by such water level change is superimposed on the ambient regional tectonic stress field (please see pp.6 rows 120-127). First of all, we do not claim that normal vertical stress is zero. Moreover, being under the influence of gravity, the vertical stress depends on the hypocentral depth. Our model is based on the water level change effect being only on horizontal components of the normal effective stress (as was shown previously for the reservoir-induced seismicity by Simpson 1976, and then for large-scale surface water level fluctuations, in Belferman et al., Eq.10b and corresponding text in p.393). Simpson (1976) established that in all faulting environments, the vertical stress increase from water loading is eventually canceled out by increased pore pressure and the final, post-diffusion stage (as explained above), is one in which the vertical stress returns to its initial value. Secondly, assuming that the reviewer is referring to Ein Feshkha boreholes, as we noted above, their relationships with faults are poorly established, as is the historical activity of the nearby fault (Sharon, et al., 2020).
  On the hydrological aspect, we expand our response above for artesian waters around Ein-Feshkha. The shallow artesian aquifers mentioned by the reviewer are of the type described by Mazor et al. (1995) for the Dead Sea rift. These are isolated and local aquifers, trapped in the fine sediments. In the Dead Sea area, such aquifers occasionally seep, as reported by sinkhole studies (e.g. Al-Halbouni et al., 2017). The fluids spewed out are described as “sediment-laden”, and we interpret this to indicate suspension of fine-grain material from the shallow hydrologic system. These local effects do not necessarily represent the deeper aquifers that might be connected to the surface via fault zones as described above. Earlier descriptions of artesian water in drill holes (Shiftan, 1958; Bentor, 1961) also tap local aquifers that do not interact with active faults (at least during the last two millennia).
  
  Comment 3:
  - The reviewer doubts the assumption that the pore pressure throughout the Dead Sea Basin at any depth responds elastically to changes in the lake level. According to the reviewer, since the basin is mostly made of clay, having plastic properties, changing the water level by 25 meters will not affect the depth of 2-3 km.
  Response:
  With regard to the composition of the Dead Sea deposits, it was shown that clay is a minor component of the Dead Sea Basin (e.g. Frydman et al., 2008; Herut et al., 1997; Haliva-Cohen et al., 2012). Frydman et al., (2008) measured geotechnical properties and found vanishing cohesion, as opposed to any lithology dominated by clay minerals. They stated that the particle size is clay-size but the mineralogy is not. Herut et al., (1997) and Haliva-Cohen et al. (2012) characterized the mineralogies and (like others) found quartz and carbonates to be the leading detrital minerals.
  
  In summary, the reviewer seems to have misinterpreted some key points in our work. In our revision, we endeavor to better present our assumptions and results to avoid confusion. With the present knowledge of the hydrological and lithological properties of the Dead Sea Basin, as documented by current literature as referenced, our assumptions and conclusions remain intact.
  
  REFERENCE
  Aldersons, F., Ben-Avraham, Z., Hofstetter A., Kissling E., Al-Yazjeen T., 2003. Lowercrustal strength under the Dead Sea basin from local earthquake data and rheological modeling. Earth Planet. Sci. Lett. 214, 129–142.
  Al-Halbouni, D., Holohan, E.P., Saberi, L., Alrshdan, H., Sawarieh, A., Closson, D., Walter, T.R. and Dahm, T., 2017. Sinkholes, subsidence and subrosion on the eastern shore of the Dead Sea as revealed by a close-range photogrammetric survey. Geomorphology, 285, pp.305-324.
  Belferman M., Katsman R. and Agnon A., 2018.Effectoflarge-scalesurfacewaterlevel fluctuationsonearthquakerecurrenceintervalunderstrike-slipfaulting. Tectonophysics,744,390-402.
  Bentor, Y.K., 1961. Some geochemical aspects of the Dead Sea and the question of its age. Geochimica et Cosmochimica Acta, 25(4), pp.239-260.
  Davies R., Foulger G., Bindley A., Styles P., 2013. Induced seismicity and hydraulic fracturing for the recovery of hydrocarbons. Mar. Pet. Geol. 45, 171–185.
  Foulger GR, Wilson MP, Gluyas JG, Julian BR, Davies RJ. 2018. Global review of human-induced earthquakes. Earth-Sci. Rev. 178:438–514
  Frydman S., Charrach J., & Goretsky I. 2008. Geotechnical properties of evaporite soils of the Dead Sea area. Engineering geology, 101(3-4), 236-244.
  Godey S., Bossu R., Guilbert J., Mazet-Roux G., 2006. The Euro-Mediterranean Bulletin: a comprehensive seismological Bulletin at regional scale. Seismol. Res. Lett. 77, 460–474.
  Gupta H.K., 1992. Reservoir induced earthquakes. In: Gupta, H.K. (Ed.), Development in Geotechnical Engineering. 71. Elsevier, Amsterdam, pp. 1–364.
  Gupta H.K., 2002. A review of recent studies of triggered earthquakes by artificial water reservoirs with special emphasis on earthquakes in Koyna, India. Earth Sci. Rev. 58 (3), 279–310.
  Gupta H.,K.,2018,Reservoir triggered seismicity at Koyna, India, over the past 50 yrs. Bulletin of the Seismological Society of America 108.5B:2907-2918.
  Haliva-Cohen A., Stein, M., Goldstein, S. L., Sandler, A., & Starinsky, A. (2012). Sources and transport routes of fine detritus material to the Late Quaternary Dead Sea basin. Quaternary Science Reviews, 50, 55-70.
  Hamiel Y., Lyakhovsky, V., & Agnon, A. 2005. Rock dilation, nonlinear deformation, and pore pressure change under shear. Earth and Planetary Science Letters, 237(3-4), 577-589.
  Herut B., Gavrieli, I., & Halicz, L. 1997. Sources and distribution of trace and minor elements in the western Dead Sea surface sediments. Applied geochemistry, 12(4), 497-505.
  Hua W., Chen, Z., Zheng, S., and Yan, C., 2013b. Reservoir induced seismicity in the Longtan reservoir, southwestern China. J. Seismol. 17 ( 2) 667-681.
  Ingebritsen S. E., & Manning, C. E. 2010. Permeability of the continental crust: dynamic variations inferred from seismicity and metamorphism. Geofluids, 10(1‐2), 193-205.
  Kirby B.J., 2010. Micro- and Nanoscale Fluid Mechanics: Transport in Microfluidic. University Press, Cambridge.
  Mazor, E., Gilad, D. and Fridman, V., 1995. Stagnant aquifer concept Part 2. Small scale artesian systems-Hazeva, Dead Sea Rift Valley, Israel. Journal of Hydrology, 173(1-4), pp.241-261.
  Rajendran K., Talwani, P., 1992. The role of elastic, undrained, and drained responses in triggering earthquakes at Monticello Reservoir, South Carolina. Bull. Seismol. Soc. Am. 82 (4), 1867–1888.
  Rice J.R., Cleary, P.M., 1976. Some basic stress diffusion solutions for fluid-saturated elastic porous media with compressible constituents. Rev. Geophys. 14 (2), 227–241.
  Shamir, G., 2006. The active structure of the Dead Sea Depression. Geol. Soc. Am. Spec. Pap. 401, 15–32.
  Sharon M., Sagy, A., Kurzon, I., Marco, S., & Rosensaft, M. 2020. Assessment of seismic sources and capable faults through hierarchic tectonic criteria: Implications for seismic hazard in the Levant. Natural Hazards and Earth System Sciences, 20(1), 125-148.
  Shiftan, Z.L. 1958. An artesian Aquifier of the Dead Sea. Bull. Research Council of Israel, 76, 27-52.
  Simpson, D. W. (1976). Seismicity changes associated with reservoir loading. Engineering Geology, 10(2-4), 123-150.
  Simpson D.W., Leith, W., Scholz, C., 1988. Two types of reservoir-induced seismicity. Bull. Seismol. Soc. Am. 78, 2025–2040.
  Simpson D. W., Stachnik, J. C., & Negmatoullaev, S. K. (2018). Rate of change in lake level and its impact on reservoir triggered seismicity. Bulletin of the Seismological Society of America, 108(5B), 2943-2954.
  Talwani P., 1997. On the nature of reservoir induced seismicity. Pure Appl Geophys. 150, 473-492.
  Talwani P., Acree, S., 1985. Pore pressure diffusion and the mechanism of reservoir induced seismicity. In: Shimazaki, K., Stuart, W. (Eds.), Earthquake Prediction. Birkhäuser, Basel, pp. 947–965.
  Talwani P., Chen, L., Gahalaut, K., 2007. Seismogenic permeability, ks. J. Geophys. Res. Solid Earth 112 (B7).
  Tomic J., Abercrombie, R., Do Nascimento, A., 2009. Source parameters and rupture velocity of small M≤2.1 reservoir induced earthquakes. Geophys. J. Int. 179, 1013–1023.
  van der Elst NJ, Page MT, Weiser DA, Goebel TH, Hosseini SM. 2016. Induced earthquake magnitudes are as large as (statistically) expected. J. Geophys. Res. 121:4575–90
  Wang H., 2000. Theory of Linear Poroelasticity With Applications to Geomechanics and
  Hydrogeology. University Press, Princeton.
  Yechieli, Y. and Bein, A., 2002. Response of groundwater systems in the Dead Sea Rift Valley to the Nuweiba earthquake: Changes in head, water chemistry, and near‐surface effects. Journal of Geophysical Research: Solid Earth, 107(B12), pp.ETG-4.
  Yehya A., Yang Z., & Rice J. R., 2018. Effect of fault architecture and permeability evolution on response to fluid injection. Journal of Geophysical Research: Solid Earth, 123, 9982–9997.
  
  Reply
  
  Citation: https://doi.org/10.5194/nhess-2021-62-AC1

Mariana Belferman et al.

Viewed

Total article views: 210 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
177	28	5	210	1	0

HTML: 177
PDF: 28
XML: 5
Total: 210
BibTeX: 1
EndNote: 0

Views and downloads (calculated since 24 Mar 2021)

Month	HTML	PDF	XML	Total
Mar 2021	98	22	5	125
Apr 2021	79	6	0	85

Cumulative views and downloads (calculated since 24 Mar 2021)

Month	HTML	PDF	XML	Total
Mar 2021	98	22	5	125
Apr 2021	79	6	0	85

Viewed (geographical distribution)

Total article views: 198 (including HTML, PDF, and XML) Thereof 198 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 20 Apr 2021

Short summary

Internal fluid pressure in pores leads to breaking. With this mechanical principle and a correlation between historical water level changes and seismicity, we explore possible variants for water level reconstruction in the Dead Sea Basin. Using the best-correlated variant, an additional indication is established regarding the location of historical earthquakes. This leads us to propose a certain forecast for the next earthquake in view of the fast and persistent dropping level of the Dead Sea.


Total:	0
HTML:	0
PDF:	0
XML:	0