A Review a Review

e-Journal Earth Science India: www.earthscienceindia.info Popular Issue, October, 2009

Ground Fissures in Uttar Pradesh – A review

Deepak Srivastava

The geological and geophysical study suggest that micro-cracks development possibly due to imperceptible neo-tectonic pulses wherein soil condition is congenial and density of micro-cracks are more and coalesce together due to sudden infiltration of surface water and causing failure of ground surface.

The natural hazards are always the curse on human being and witnessed ever since the dawn of civilizations. One such lesser-known activity is the ground cracks in Uttar Pradesh which has drawn the attention of scientific community at large and Quaternary geologist in particular. Although ground fissures are not uncommon but the unprecedented occurrences of such phenomena during 2008 in several districts of Uttar Pradesh has raised alarming bell both in respect of scientific modeling and societal overtures.

The several incidences of ground fissures have been reported from different parts of Uttar Pradesh for the last few years. Initially, the ground fissures were reported from parts of Gangetic plain in areas viz Chihibramau, Nawabganj, Kamlaganj and Kannauj of Farrukhabad district in June-July 1995, Baripal village of Kanpur Dehat, Malkhanpur village of Allahabad, Anegpur & Sonepur villages of Sant Ravidas Nagar during June-July 2006, from Karanda village of Ghazipur district 2006. In Gangetic plain of Uttar Pradesh within the confinement of quaternary sediments ground fissures again reported from 90 locations falling in the districts of Hamirpur, Etawah, Banda, Fatehpur, Chitrakoot, Kanpur Dehat, Allahabad, and Lucknow in June-July 2008. Considering the scientific importance and social responsibility, the Geological Survey of India carried out a multidisciplinary study involving quaternary geology, geomorphology, groundwater, geotechnical and geophysical studies.

Bases on this observations the study suggest that all these cracks have developed in the close vicinity of major river/streams, after the first heavy rainfall of the year. The rainfall data of the previous years witnessed poor rainfall. During 2008 in the months of June-July there was heavy shower leadinging to the development of cracks. Most of the cracks are curvilinear in shape and very from a few meters up to 1 km in length, and a maximum opening of about 1m. The cracks have widened because of subsequent collapse of the edges of the walls leading to increase in their aperture The cracks have reticulate pattern and sympathetic cracks are seen on adjacent surface of the cracks. Vertical displacement was not discernible. It was also gathered from local inhabitants that no acoustic or tremors felt in the area.

The terrain morphology indicates a slightly undulating and low-lying character. Silty clay is the dominant surfacial unit followed by sand. The cracks developed are of various length from 15m to 200m and 0.5 – 1.5 in depth. The major trends in Hamirpur district is along N 70º W – S 70º E with complementary branches along N 10º E – S 10º W to N 25º E – S 25º W. In district Mahoba the cracks are oriented along N 75º E – S 75º W and that of Etawah district it is along N 50º E – S 50º W. In Lucknow district, curvilinear discontinuous cracks of about 50 m length, 0.70 – 1.0m depth with a maximum aperture of 1m have developed in village Dulukhera in Kakori Tehsil and trending N 10º E – S 10º W direction and gradually turns S 70º W. The character of soil profile is silty clay followed by clay with kankar horizon. The ground water table varies from 40 to 60m.

Fig.-1: Location of Ground Fissures in U.P. (incidences between June 8 – 15’ 2008)

To understand the sub-surface nature of the cracks a GPR Survey was taken up. The study has indicated that on an average the cracks are shallow to very shallow depth (maximum 6m deep).

To decipher the seismic inputs in resulting the cracks four MEQ station was established in Hamirpur district and the continuous monitoring seismic events carried out for two and half months during June-August 2008. The result show 3 to 4 events of small magnitude of less than 1.5m on Richter scale confined to shallow depth between 2 to 5 km. The geological and geophysical study suggest that Micro cracks development possibly due to imperceptible neo tectonic pulses wherein soil condition is congenial and density of micro cracks are more and coalesce together due to sudden infiltration of surface water and causing failure of ground surface. However, data so suggests needs further in depth studies and analysis. The general conception of heavy ground water withdrawal in the area and sudden recharge are the causes of fissure development also need careful scientific studies. The alluvial plains of U.P. has witnessed ground fissures/cracks causing concern among public, administration and scientific communities. The fissures are commonly occurring in the end phase of summer and at the onset of first rainfall of pre-monsoon period. These fissures vary from a few meters to more than a kilometer in length and are discontinuous in nature with surface opening varying from 0.15m to 1.5m in width. The depth ranges from 1m to 6m below ground level. The cracks are generally curvilinear and show a reticulate pattern at places. Predominently these are developed in Newer Alluvium Sequences and data collected so far suggest prolong draught followed by excessive rain resulting in tensional cracks. However, considering its frequency and localization of occurrence, asystematic study is warranted.

The ground fissures are the cracks developed on the earth surface as a natural process. Thses are popular earth surface phenomenon showing discontinuous and broken earth surface. There are several kind of ground fissures related to geological phenomenon viz tectonic,fault related, earthquake fissures (Geng Da Yu, 2000).There are several reporting of ground fissures from different parts of the world, particularly from India, China, USA, Greece, etc. Thses fissures have resulted due to seismic as well as aseismic causes. However, the cause may be any, the development of cracks on ground has been cause of concern for for the public, planner, earth scientists etc. Hence, the scientific community at large and Quaternary geologist in particular took keen interest in studying these causes and consequences fo these cracks. Considering the scientific importance and social responsibility, Operation U.P.& Uttarakhand of Geological Survey of India, Northern Region, Lucknow took initiative and carried out a multidisciplinary study involving quaternary geology, geomorphology, groundwater, geotechnical and geophysical studies of ground fissures in Hamirpur, Allahabad, Farrukhabad, Ghazipur districts.

Since 1995, the ground fissures have been reported from several areas of Yamuna-Gangetic plain viz Chihibramau, Nawabganj, Kamlaganj and Kannauj of Farrukhabad, Baripal village of Kanpur Dehat, Malkhanpur village of Allahabad, Anegpur & Sonepur villages of Sant Ravidas Nagar, Karanda village of Ghazipur, Mataundh village of Banda, Jigni village of Hamirpur etc.. However, within the confinement of quaternary sediments ground fissures again reported from 90 locations falling in the districts of Hamirpur, Etawah, Banda, Fatehpur, Chitrakoot, Kanpur Dehat, Allahabad, and Lucknow in June-July 2008 (Table-1). Such a large number of incidences of these cracks within a short span of time caused panicy situations in the media, public and the planners, besides in the scientific community who engaged himself in finding the causes for the formation of these cracks.

Table-1: List of localities, ground crack incidences in U.P. during 2008

District Tehsil Village Date of Occurrence

Hamirpur Sarila Kupra* 09-06-08

Sarila Puraini* 09-06-08

Sarila Parcha* 09-06-08

Sarila Chandauta 17-06-08

Sarila Harsundi 20-06-08

Sarila Dhauhal Buzurg 10-06-08 Sarila Sarila 09-06-08

Maudaha Rivan* 09-06-08

Maudaha Khandeh* 09-06-08

Maudaha Karhiya 05-07-08

Maudaha Artara 16-07-08

Sadar Sikrodhi* 09-06-08

Sadar Surajpur* 09-06-08

Sadar Chaura Devi* 09-06-08

Sadar Merapur danda 09-06-08

Sadar Helapur, Chanduli tir 09-06-08

Sadar Beri 09-06-08

Sadar Gimuha Danda 09-06-08

Sadar Rithaura Dariya 09-06-08

Sadar Surauli Buzurg 12-06-08

Sadar Chandpurva 12-06-08

Sadar Ramedi Danda 16-06-08

Sadar Kharaunj 04-07-08

Mahoba Sadar Khanna* 09-06-08

Sadar Suraha 09-06-08

Charkhari Kharela June 2008

Kulpahar Shergarh June 2008

Kulapahar Rurikhurd June2008

Etawah Chakarnagar Garhi Mangat* 15-06-08

Chakarnagar Sindaus* 15-06-08

Chakarnagar Hanumantapura* 15-06-08

Chakarnagar Basaiya har* 15-06-08

Chakarnagar Vidhipur 20-06-08

Jalaun Madhogarh Rampura* 12-06-08 Madhogarh Ninwali June -July 2008

Kalpi Kalpi* 12-06-08

Kalpi Guhra Khas June -July 2008

Kalpi Baggi June -July 2008

Kalpi Nyamatpur June -July 2008

Kalpi Taribulda June -July 2008

Fatehpur Bindki Shivri June -July 2008

Bindki Khadara June -July 2008

Bindki Behta June -July 2008

Khaga Sujanpur June -July 2008

Khaga Galehara June -July 2008

Khaga Ghoshi June -July 2008

Khaga Belai June -July 2008

Kanpur Dehat Sikandara Ladpur 13-06-08

Sikandara Ghasbara 13-06-08

Sikandara Naipalpur 20-06-08

Sikandara Khalagaon 06-07-08

Bhognipur Birma 19-06-08

Banda Sadar Mataundh* 12-06-08

Raibareli Maharajganj Raghavpur 15-06-08

Maharajganj Saraiya Majare Bhawanigarh 05-07-08

Lalganj Saraila June 2008

Sadar Lodhwari June 2008

Lucknow Kakori Dullu Khera* June-July 2008

Note : Villages marked as * Geologically studied by Geological Survey of India.

FISSURE MORPHOLOGY

The ground fissures in the studied area vary in size and shape. They are curvilinear and show a reticulate and branching pattern (Fig.2 & Photo-1). The cracks are of various length from 15m to 1km and 0.5 – 1.5 in depth and vary in width from a few centimeters to about a meter. The GPR studies of the crack at Jigni village, Hamirpur shows maximum depth about 6meter. The two sides of the cracks are vertical and there is no elevation difference between the two walls of the crack (Photo - 1 to 9). GPR Survey by Antarctica Division, GSI, Faridabad. It was concluded that on an average the cracks were shallow to very shallow As indicated by the GPR study, the sub-surface depth of ground fissures at Jigni was upto 6m, at Parchha upto 3m and at Khandeh only surficial. These cracks did not affects the tree on their way. However they have extended in the birck wall and have damaged the concrete road (Photo 4, 7 & 8).The intensity of fissuring was different at different locales. In Chaura Devi Temple site and Kupra site in Hamirpur, the crack has damaged the brick wall and concrete road but in Parcha site the aggressing crack did not affect even the mud wall of a house.

In these areas the basement is as deep as 30m below the surface and it is characterized by granitic rocks. The basement rocks are characterized by a NNE-SSW, NW-SE and nearly E-W trends The major trends in Hamirpur district is along N 70º W – S 70º E with complementary branches along N 10º E – S 10º W to N 25º E – S 25º W. In district Mahoba the cracks are oriented along N 75º E – S 75º W and that of Etawah district it is along N 50º E – S 50º W. In Lucknow district, curvilinear discontinuous cracks of about 50 m length, 0.70 – 1.0m depth with a maximum aperture of 1m have developed in village Dulukhera in Kakori Tehsil and trending N 10º E – S 10º W direction and gradually turns S 70º W. The cracks have widened because of subsequent collapse of the edges of the walls along the sympathetic cracks leading to increase in their aperture The sympathetic cracks have been observed parallel to length of the crack.

ASSOSCIATION WITH DRAINAGE AND RAINFALL

The studies show that the crack have developed in the close vicinity of major river/streams, after the first heavy rainfall of the year.streams. A plot of the recent crack locations (Fig.2) show that in Hamirpur, Jalaun, Kanpur Dehat and Fatehpur diastricts, these cracks are very close to the Yamuna or the Betwa rivers. These areas are characterized by the high water table gradient. These being the ravenous terrain, the drainage density are also very high in these areas.

The rainfall data from the district authorities show that the area witnessed very poor rainfall for the previous four years. In particular, the rainfall during the month of June was much below the average. However, in June 2008, immediately before the incidence of fissuring, there had been heavy rainfall, multiple times the average rainfall, in all these areas.Because of scanty rainfall, large number of new bore wells extracting huge quantity of ground weter was erected in the area to fetch the needs of villager.

Drainage , Topography and Soil profile

The area is characterised by undulating topography. In Hamirpur, Jalaun, Kanpur Dehat, Fatehpur etc the fissures have developed in the ravenous topography. The drainage density in these areas are very high. These small streams drains into the majors streams viz. Yamuna/Betwa river. Such a differenc in topography also provides high gradient for the sub-surface ground water flow. The ground water table varies from 40 to 60m.

Silty clay is the dominant surficial unit followed by sand. The character of soil profile is silty clay followed by clay with kankar horizon. There are kankar+clay horizon at different layers in soil profile (Photo 3). Such layers constitute the impermeable horizons for percolation of ground water.

MECHANISM FOR FORMATION OF CRACK

In general, ground fissures may be caused by (1) surface rupture along faults, either as a primary rupture on the seismogenic fault or as a sympathetic rupture ; (2) secondary movement on shallow faults; (3) shaking-induced compaction of natural deposits in sedimentary basins and river valleys, or artificial fills; and (4) liquefaction of loose sandy sediment (USGS Response to an Urban Earthquake -- Northridge '94). Hence, broadly two type of mechanism have been suggested. First, seismic (Dou et al., 2005) and second, aseismic which is related to ground water extraction. It has been found that the preexisted faults are serving as the bases of forming modern ground fissure, and human activities, e.g. over pumping ground water, or oil, can accelerate the creeping of the fissures and make them destructive to many kinds of civil engineering (Geng Da Yu,2000). E. Lekkas et.al. (1996) have described the ground fissures in Greece as related lo distructive earthquake leading to liquefaction, ground fissures and coastline change during the Egio earthquake (15 June 1995; Central-Western Greece)

Photo-1 Curvilinear Crack Photo-2: Sympathetic curvilinear Photo-3: Soil profile with showing branching and & radiating crack on the ground natural cave Village reticulate pattern Village Village Puraini, District Rampura, District Jalaun Kupra, District Hamirpur Hamirpur

Photo 4: Curvilinear crack Photo -5: Collapse of side walls along Photo -6: Extension of cavity on cutting across the metalled sympathetic cracks on the ground, the ground surface Village road. Chaura Devi Temple, Village Puraini, Tehsil Sarila, District Rampura, District Jalaun District Hamirpur Hamirpur

Photo-7: Crack in the inner Photo-8: Crack in the Photo-9: Caving in the side of wall of the house. outer brick & Cement wall road and section of the Village Surajpur, and floor of the house . crack Village Basaiahar, District Hamirpur Vill age Surajpur, District District Etawah

Photographs showing different features of Ground Fissures

The fissures attributed to earthquake ( e.g. Northridge earthquake, California, U.S.A.) includes zones of ground fissures and extensional cracking, lateral displacements, settlements with vertical displacements, and compressive deformation in the form of soil and pavement warps and buckles. Further, these occur near the epicenter and above the fault- rupture plane. USGS scientists , in California ground failure sites have evaluated two mechanisms of localized soil failure and secondary tectonic deformation. On the basis of geologic structure and cone-penetration tests it was observed that ground failure sites were underlain by saturated soils that could be expected to fail when subjected to high levels of ground shaking. Therefore, localized failure in a buried layer was thought to be the mechanism causing the failure at the surface. But the present area is under aseismic zone and there is meager chance of any earthquake related cause for formation of cracks. Still, in order to decipher the seismic inputs, four MEQ station was established by GSI in Hamirpur district and the continuous monitoring seismic events carried out since August 2008. . The result show 3 to 4 events of small magnitude of less than 1.5m on Richter scale confined to shallow depth between 2 to 5 km. The geological and geophysical study suggest that Micro cracks development possibly due to imperceptible neo-tectonic pulses wherein soil condition is congenial and density of micro cracks are more and coaless together due to sudden infiltration of surface water and causing failure of ground surface. However, data so suggests needs further in depth studies and analysis. The general conception of heavy ground water withdrawal in the area and sudden over saturation of soil profile within a short span of few hours may have caused sub-surface flow of ground water within clay-silt layer lead to development of ground caves. The ground cave-in was reported at Karanda village (Ghazipur district). The study indicated dissolution of earth material and soil liquefaction of subsurface sediments as a cause of collapse (Kar, 2006). Similar cave were observed in Rampura (District Jalaun) and Basaiahar (District Etawah) during recent crack (Photo-3,7&8). The lowering of the water table was considered to be the main mechanism for ground cracking. The cause of ground cracks was attributed to the ground water fluctuations and saturation of soil column due to rains. It was also reported that these types of ground cracks generally take place at the interface of dry-wet seasons. It was believed that the removal of water from soil and clay particles reduces pore pressure and as a consequence effective pressure is increased. This led to consolidation, the degree of which depends on compressibility of material involved. The net result was compression and cracking. Similar kind of mechanism have been suggested for ground fissures in Xien province in China. Large-scale extraction of ground water has resulted in significant drawdown of the phreatic surface and in land subsidence across. It has also triggered the rejuvenation of the normal faults in the upper portions of the Quaternary deposits, leading to surface rupturing and the development of ground fissure zones.

CONCLUSIONS

• All the cracks are curvilinear.

• The cracks are developed on Alluvium comprising silty clay with clay and kanker layers.

• All are located in the vicinity of some streams.

• All have been noticed after the first heavy rains in the area.

• All the areas have been experiencing deficient rainfall during 4-5 years.

• No vertical displacement is discernible along the crack.

• It was reported that no acoustic or tremors were associated with the formation of cracks.

• The cause of the ground fissure has been attributed to the excessive withdrawal of groundwater and sudden over-saturation of soil profile due to heavy rain fall over a short duration of about two hours.

• Besides the ground water reasons, piping i.e. removal of fines with the sub-surface flow of water may also trigger and develop the problem.

• As such the phenomenon does not appear to be such which can create a panic situation.

RECOMMENDATIONS

• Keeping in view, the large number of incidences in different area of Uttar Pradesh, a full fledged investigation of these cracks by implying the geophysical, geomorphological, groundwater , geological and geotechnical studies is required. The Geological Survey of India has taken a lead initiative in this regard and wishes to involve State Groundwater Board, Central Groundwater Board and Uttar Pradesh Directorate of Geology and Mining in this endeavor. The Micro-Earthquake Equipment has already been installed in Surajpur Village of Hamirpur to rule out the possibilities of micro tremors.

• As mitigation method, the recharge of the groundwater should be taken up on priority basis by formulating the comprehensive plan for ground water harvesting and water management in the region