Recent repeated occurrences of Gas bubbles streaming … T.R.K., Santosh , M. (2013), Proterozoic...

INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES

Volume 4, No 3, 2014

© Copyright 2010 All rights reserved Integrated Publishing services

Research article ISSN 0976 – 4380

Submitted on August 2013 published on February 2014 573

Recent repeated occurrences of Gas bubbles streaming water jets along

Achankovil shear zone of south India and their seismotectonic significance Manimaran G, Sugan M

School of Tectonics, Department of Geology, V.O.Chidambaram College, Tuticorin

628 008, India.

[email protected]

ABSTRACT

Achankovil shear zone is a major tectonic crustal segment of south India.The recently

observed gas bubbles streaming water jets in the ponds along the shearzone and the minor

tremors released between the years 2005-2013 are pointing out the neotectonic activation of

Achankovil shearzone,a manifestation of the forthcoming major seismotectonic activities of

Indian plate.

Keywords: Achankovil shear zone, gas bubbles, water jets.

1. Introduction

The Achankovil Shear Zone is a well deciphered lineament of 8-25 Km width on LANDSAT

imageries and aerial photos mosaic trending WNW-ESE to NW-SE direction and it

represents a tectonic crustal break bisecting the southern portion of south India (Manimaran

1995).Lineaments,faults and shears of large and small dimensions of both dextral and

sinistral are very well developed in the Charnockitetic – Gneissic terrain of Achankovil Shear

Zone Drury and Holt 1980; santosh 1984; Ravindra Kumar and Chacko 1986;Manimaran and

Roy chacko 1996; Sacks et al., 1997; Guru Rajesh and Chetty 2006; Manimaran et al 2007;

RamaKrishnan and Vaidyanathan 2008; Rajesh 2012; Manimaran et al 2013; Tomson et al

2013and Chetty and Santosh 2013, (in press).

Recently Gaitan Vaz et al. (2006) have reported the thermal springs from reactivated deep

seated E-W trending faults from Manamelkudi Coastal area, west of Palk Bay of India.

Sudden spurt of subsurface water oozing at Kalayat village in Jind District of Haryana

coupled with occurrence of a major earthquake in the Hindukush region on 13th December

2005 and possible connection with Saraswathi Palaeochannel were identified by Bhadra et al

(2006). After the release of the two consecutive tsunamigenic great earthquakes (Mw 9.3 and

M 8.7) from Northeastern Sumatra offshore region on 26.12.2004 and 28.3.2005, Southern

Granulite Terrain of South India have been experiencing the minor tremors (Ramasamy et al.

2006) and microseismic fracturing in lands especially along weak shear zones.

2. Recent tremors and waterjets

An induced minor Tremor (M>3) at Kuppanapuram village, Kayathar Panchayat of Tuticorin

District and southeasterly microfracturing of land and houses between Kayathar and

Tuticorin were occurred on 30.3.2005, as a consequence of release of M 8.7 Northeastern

Sumatra earthquake on 28.3.2005. After Kayathar minor tremor, on 10.4.2005 there was

sudden spurt of continuous upward streaming of gas bubbles with oozing water jets upto

40cm high above water surface in a waterpond at Karisalkulam (N 80 59’ 50” and E 770 47’

48”) near Kayathar (Figure 1). There were more than 50 spots of oozing water jets for a

Recent repeated occurrences of Gas bubbles Streaming Water Jets along Achankovil shear zone of south

India and their seismotectonic significance

Manimaran G, Sugan M

International Journal of Geomatics and Geosciences

Volume 4 Issue 3, 2014 574

length of 10 metres in NW-SE direction. The above location is situated near the northern

boundary of the Achankovil Shear zone and the noising water jets were lasted after 3 days.

Figure 1: The figure showing the regime of Achankovil Shear Zone and locations of gas

bubbles streaming water jets at 1. Karisalkulam 2. Thottiyankulam 3. Pavurchattram

Later from the same shear zone, the oozing of red coloured water from Paddy field at

Kottarankurichi near Veeravanallur and also from dry land at Kadaiyam of Tirunelveli

district were noticed on 10.7.2005 and on 7.8.2005 a minor tremor (M≥3) was occurred at

Srivaikundam of Tuticorin District (Figure 1).

During the Northeast Monsoon, at the end of October 2006 the ponds and wells of Tirunelveli

and Tuticorin Districts were flooded and filled due to heavy rains. Strangely on 10.11.2006

the local people have noticed that there were sudden upcoming of continuous gas bubbles

with oozing water jets upto a height of 30-60 cm producing ripples in a pond at

Thottiyankulam (N80 49’50” and E 770 32’6”) near Alangulam (Fig. 2, 3 and 4) More than

100 spots of gas streaming water jets aligned along a two linear sinuous fractures of 20

metres length (East) and 30 metres length [west], separated by a distance of 600 metres. Both

fractures are striking N 60-650 W – S60-650 E direction. Below the warm spots of escaping

gas bubbles, vertical cavities of 10 cm to 20 cm size were observed on these fractures. The

standing water on these fractures was less than one metre. The speed of upcoming –

humming gas bubbles of 2 to 10 cm size was 10-20 cm/sec. Oozing of water jets gradually

decreasing in frequency and intensity stopped after a month on 20.12.2006.






Figure 2: Many spots of gas bubbles upstreaming water jets are observed by local people at

Western side of Thottiyankulam, near Alangulam. Water jets clear spots are

completely flanked by a green algae like a blanket.

Figure 3: Three major spots of submissive water jets observed in a clear water along

Eastern side of Thottiyankulam, near Alangulam.






Figure 4: Close view of a submissive water jet in Thottiyankulam pond producing

continuous ripples in water surface

One week earlier to Thottiyankulam event, a well (N 8052’12” and E 77022’30”) at 300

metres east of Pavurchattram bus stand was noticed with 20 spots of gas bubbles streaming

water jets. The well is located on a highly fractured quartzite striking NW-SE direction. The

escaping gas bubbles were 5 cm to 15 cm size producing ripples on groundwater surface at 6

feet depth (Fig.5) and water jets were disappeared at the end of December 2006. The warm

water samples with gas bubbles collected upto half bottles from pond at Thottiyankulam and

well at Pavurchatram were examined with portable Micro Radioactive Survey Meter and all

samples showed values below normal radon radioactivity (Between 094-050 Millirem/hour)

and possibility of radioactivity radon gas emission was rejected.

Figure 5: A well showing continuous upcoming gas bubbles streaming water jets at

Pavurchattram






3. Seismotectonic significance

The most important is that the above two locations are 18 km apart and both of them located

on the NW – SE running main fracture zone of Achankovil shear zone which warrants helium

gas survey study for these locations (Fig.1). The release of minor tremors and oozing of water

in ponds and lands along the Achankovil shear zone are pointing out the ongoing neotectonic

activities. The release of world recorded second largest Sumatra great earthquake (Mw 9.3)

has intensely affected the area around epicenter for a radius of 2000 Km and more than 2000

aftershocks have been released (20 shocks per week) along Andaman – Indonesia Subduction

zone upto December 2006, Lasitha et al (2006) ; Manimaran(2007); Manimaran and Renuga

(2007). These continuous release of aftershocks have initiated reactivation and minor

differential uplift of different crustal segments (Transpression) bounded by N-S, NW-SE,

NE-SW and E-W running deep Shear Zones of South India.

A microseismic Tremor was released at Achankovil Shear Zone on 16-9-2012. The People of

the Achanputhur,Vadakarai,Vaavanagaram and Parvathipuram were experiencing Seismic

Shock Waves after hearing a Huge noisy sound at 11.30 AM on Sunday 16-9-2012. The same

day minor tremors were experienced by the people of Achanpudur at 4.30 PM and 6 PM .The

middle tremors extended for 2 seconds while at first and last tremors Shocking were less than

a second. Huge sound followed by a shocking seismic waves and moving chairs, tables and

utensils were experienced. Fracturing of 20 houses were reported at Achanputhur. At

Vaavanagaram (North 090 02’ 872” ; E 770 17’ 268”) the land and two houses were cracked

by conjugate fracturing along prominent east-west open Fracture for a length of 30 meters

and subordinate North-south fracture for 21 meters .the above Features suggest that the

Intesity of earthquake was approximately ≤ M3. It may be considered as a far-off Foreshock

of a Forthcoming high intensity earthquake of the Indian plate- the adjoining lithospheric

plates i.e. Sunda, Australia and Burma plates. A minor tremors were recently released at

Kalakadu on 13-10-2012 : at Pavurchathiram on 20-11-2012 and at vadakarai near Tenkasi

on 7-6-2013.

4. Conclusion

These microseismic activities along the Achankovil shear zone proves that the shear zone is

neotectonically still active. Hence the streaming of gases in the pond along the Achankovil

shear zone is due to the present neotectonic activities of the shear zone.

Acknowledgement

The authors express their sincere thanks to Mr. A.P.C.V. Chockalingam, Secretary and

Dr.C.Verabahu, Principal, V.O.C. College, Tuticorin, South India.

5. References

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Village, Jind District, Harayana in December, 2005: Possible Connection with

Saraswathi Palaeochannel, Journal of Geological Society of India, 68, pp 946-948.

2. Chetty, T.R.K., Santosh , M. (2013), Proterozoic Orogens in Southern Peninsular

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