Mud Volcano In Java May Continue To Erupt For Months And Possibly Years
Pastor Dale Morgan
Mud Volcano In Java May Continue To Erupt For Months And Possibly Years*
A mud volcano gryphon. Mud volcanoes are extrusions of a water and mud
mix on the earth's surface that form cone-shaped volcanoes. These can be
metres to kilometers wide and metres to hundreds of metres thick. They
commonly occur in convergent tectonic settings, such as Azerbaijan, in
front of deltas, such as the Mississippi and due to the gravitational
collapse of continental margin sediments such as the Niger Delta.
by Staff Writers
Durham UK (SPX) Jan 25, 2007
The first scientific report into the causes and impact of Lusi, the
Indonesian mud volcano, reveals that the 2006 eruption will continue to
erupt and spew out between 7,000 and 150,000 cubic metres of mud a day
for months, if not years to come, leaving at least 10 km2 around the
volcano vent uninhabitable for years and over 11,000 people permanently
displaced.
The paper by a Durham University-led team and published in the February
issue of GSA Today (1), reveals that the eruption was almost certainly
manmade and caused by the drilling of a nearby exploratory borehole (2)
looking for gas, reinforcing the possible explanation in a UN report (3)
from July last year.
The mud volcano, known locally as 'Lusi', has been erupting for 239 (4)
days and has continued to spew between 7,000 and 150,000 cubic metres of
mud out every day, destroying infrastructure, razing four villages and
25 factories. Thirteen people have also died as a result of a rupture in
a natural gas pipeline that lay underneath one of the holding dams built
to retain the mud. It first erupted on 29 May 2006 in the Porong
subdistrict of Sidoarjo in Eastern Java, close to Indonesia's second
city of Surabaya.
The team of mud volcano and pressure experts, who analysed satellite
images of the area for their study, propose that a local region around
the central volcano vent will collapse to form a crater. In addition an
area of at least the dimensions of the flow (10km2) will probably sag
over the next few months and years.
Seepage of mud and water are common on earth but usually a preventable
hazard when exploring for oil and gas.
Mud volcano expert, Professor Richard Davies of Durham University's
Centre for Research into Earth Energy Systems (CeREES) comments: "It is
standard industry procedure that this kind of drilling requires the use
of steel casing to support the borehole, to protect against the pressure
of fluids such as water, oil or gas.
"In the case of Lusi a pressured limestone rock containing water (a
water aquifer) was drilled while the lower part of the borehole was
exposed and not protected by casing. As a result rocks fractured and a
mix of mud and water worked its way to the surface. Our research brings
us to the conclusion that the incident was most probably the result of
drilling."
"Lusi is similar to a 'blow-out' (eruption of water at the surface) that
happened offshore of Brunei in 1979. Just as is most probably the case
with Lusi, the Brunei event was caused by drilling and it took an
international oil company almost 30 years and 20 relief wells and
monitoring before the eruption stopped."
Prof. Davies continued: "Up to now scientists have known relatively
little about mud volcanoes and Lusi has provided the first opportunity
for experts to study one from birth onwards. Our work offers a clearer
understanding of how they are created and what happens when they erupt.
"We hope that the new insights will prove useful to the oil and gas
industry, which frequently encounters pressurised fluid in rock strata
that could, if not controlled, force their way to the surface during
exploration drilling. Ultimately we hope that what we learn about this
incident can help insure it is less likely to happen again."
The team from Durham, Cardiff and Aberdeen Universities and GeoPressure
Technology Ltd, an Ikon Science company, has essentially discounted the
effect of an earthquake which occurred in the region two days prior to
the mud volcano as the cause of the eruption. This is based on the
time-lapse between the earthquake and the eruption, the fact that there
were no other mud volcanoes in the region following the earthquake and
through comparison with other geological examples.
This news release is based on the findings published in the paper: Birth
of a mud volcano: East Java (29 May 2006). Davies, R.J et al; GSA Today
v. 17, no 2 (2007) 4-9 published by the Geological Society of America.
The team involved in the study was made up of: Richard J. Davies, CeREES
(Centre for Research into Earth Energy Systems), Durham University,
Richard E. Swarbrick, Geopressure Techonology Ltd, an Ikon Science
company, Robert J. Evans, School of Earth, Ocean and Planetary Sciences,
Cardiff University and Mads Huuse, Department of Geology and Petroleum
Geology, University of Aberdeen.