1848 Marlborough earthquake
Encyclopedia
The 1848 Marlborough earthquake is the name associated with a severe earthquake which occurred at 1:40 a.m. on 16 October 1848 and whose epicenter
was in the Marlborough
region of the South Island
of New Zealand
.
In Wellington
the shaking lasted for about two minutes and caused widespread damage, especially to brick- or stone- built structures. Most of the buildings damaged in the earthquake were rebuilt in wood and this contributed to the relatively low level of damage and loss of life in the more powerful Wairarapa earthquake
that hit Wellington seven years later.
and Pacific Plate
s. In the South Island
most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, the Alpine Fault
. In the North Island
, the displacement is mainly taken up along the Kermadec subduction zone
, although the remaining dextral strike-slip component of the relative plate motion is accommodated by the North Island Fault System
(NIFS). A group of dextral strike-slip structures, known as the Marlborough Fault System
, transfer displacement between the mainly transform
and convergent type plate boundaries
in a complex zone at the northern end of South Island. The earthquake occurred on the Awatere Fault
which is part of the Marlborough Fault System.
of about 7.5 has been estimated from the rupture length and measured displacements.
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
was in the Marlborough
Marlborough, New Zealand
Marlborough is one of the regions of New Zealand, located in the northeast of the South Island. Marlborough is a unitary authority, both a region and a district, and its council is located at Blenheim. Marlborough is known for its dry climate, the picturesque Marlborough Sounds, and sauvignon blanc...
region of the South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
.
In Wellington
Wellington
Wellington is the capital city and third most populous urban area of New Zealand, although it is likely to have surpassed Christchurch due to the exodus following the Canterbury Earthquake. It is at the southwestern tip of the North Island, between Cook Strait and the Rimutaka Range...
the shaking lasted for about two minutes and caused widespread damage, especially to brick- or stone- built structures. Most of the buildings damaged in the earthquake were rebuilt in wood and this contributed to the relatively low level of damage and loss of life in the more powerful Wairarapa earthquake
1855 Wairarapa earthquake
The 1855 Wairarapa earthquake occurred on 23 January at about 9 p.m. In Wellington, close to the epicenter, shaking lasted for at least 50 seconds. The magnitude of the earthquake is estimated to have been in the range 8.1-8.3, the most powerful recorded in New Zealand since systematic European...
that hit Wellington seven years later.
Tectonic setting
New Zealand lies along the boundary between the AustralianIndo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters...
and Pacific Plate
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....
s. In the South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, the Alpine Fault
Alpine Fault
The Alpine Fault is a geological fault, more specifically known as a right-lateral strike-slip fault, that runs almost the entire length of New Zealand's South Island. It forms a transform boundary between the Pacific Plate and the Indo-Australian Plate. Earthquakes along the fault, and the...
. In the North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
, the displacement is mainly taken up along the Kermadec subduction zone
Kermadec Trench
The Kermadec trench is one of Earth's deepest oceanic trenches, reaching a depth of . Formed by the subduction of the Pacific Plate under the Indo-Australian Plate, it runs over a thousand kilometres parallel with and to the east of the Kermadec Ridge and island arc, from near the northeastern tip...
, although the remaining dextral strike-slip component of the relative plate motion is accommodated by the North Island Fault System
North Island Fault System
The North Island Fault System or North Island Dextral Fault Belt is a set of southwest-northeast trending seismically-active faults in the North Island of New Zealand that carry most of the dextral strike-slip component of the oblique convergence of the Pacific Plate with the Australian Plate...
(NIFS). A group of dextral strike-slip structures, known as the Marlborough Fault System
Marlborough Fault System
The Marlborough Fault System is a set of four large dextral strike-slip faults and other related structures in the northern part of South Island, New Zealand, which transfer displacement between the mainly transform plate boundary of the Alpine fault and the mainly destructive boundary of the...
, transfer displacement between the mainly transform
Transform fault
A transform fault or transform boundary, also known as conservative plate boundary since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly horizontal in either sinistral or dextral direction. Furthermore, transform faults end abruptly...
and convergent type plate boundaries
Convergent boundary
In plate tectonics, a convergent boundary, also known as a destructive plate boundary , is an actively deforming region where two tectonic plates or fragments of lithosphere move toward one another and collide...
in a complex zone at the northern end of South Island. The earthquake occurred on the Awatere Fault
Awatere Fault
The Awatere Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It forms part of the Marlborough Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate,...
which is part of the Marlborough Fault System.
Earthquake characteristics
The earthquake was associated with the rupturing of a minimum of 105 km of the Awatere Fault. A horizontal displacement of about 6 metres was accompanied by smaller vertical movements of varying sense. A shallow epicentral depth is inferred from the large number of felt aftershocks A moment magnitudeMoment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
of about 7.5 has been estimated from the rupture length and measured displacements.
Damage
In Wellington, almost all buildings of brick or stone construction were damaged, including homes, churches, the jail, and the colonial hospital. Most wooden buildings were undamaged, although many lost their brick chimneys. In the Marlborough region itself, a number of homesteads were badly damaged. Several buildings damaged in the main shock were destroyed during strong aftershocks over the next few days. The only fatalities from the earthquake occurred when a damaged building collapsed during one of the aftershocks.See also
- List of New Zealand earthquakes
- 1888 North Canterbury earthquake1888 North Canterbury earthquakeThe 1888 North Canterbury earthquake is the name associated with a severe earthquake which occurred at 4.10 a.m on 1 September 1888 following a sequence of foreshocks that started the previous evening, and whose epicentre was in the North Canterbury region of the South Island of New Zealand.In...
- 1843 Wanganui earthquake1843 Wanganui earthquakeThe 1843 Wanganui earthquake occurred on July 8, 1843 with an epicenter near Wanganui, North Island New Zealand. This was the first earthquake in New Zealand over magnitude 7 for which written records exist.-Tectonic setting:...