May 2006 Java earthquake

May 2006 Java earthquake

Jakarta Pangandaran Yogyakarta
Date	27 May 2006 (2006-05-27)
Origin time	05:53 local time [1]
Magnitude	6.3 Mw [1]
Depth	10 km (6 mi) [1]
Epicenter	7°57′43″S 110°27′29″E / 7.962°S 110.458°E / -7.962; 110.458Coordinates: 7°57′43″S 110°27′29″E / 7.962°S 110.458°E / -7.962; 110.458 [1]
Type	Oblique-slip
Areas affected	Yogyakarta Special Region Java, Indonesia
Total damage	Rp 29.1 Trillion ($3.1B) [2]
Max. intensity	MSK – IX (Destructive) [3]
Peak acceleration	.336g [4]
Casualties	> 5,700 dead [5][6] > 37,000 injured [5][6]

The May 2006 Java earthquake occurred at 05:54 local time on 27 May on the southern coast of the island of Java, around 20 km (12 mi) south-southeast of the Indonesian city of Yogyakarta. The shock occurred at a shallow depth and was located just to the south of Mount Merapi, a stratovolcano (that was mid-eruption at the time) located on the border between Central Java and Yogyakarta. The large M6.3 earthquake caused a disproportionate number of casualties, with more than 5,700 deaths and 37,000 injuries, and very high financial losses (Rp 29.1 Trillion ($3.1B)). With a lack of instruments in the area, the shock was initially attributed with the (strike-slip) Opak Fault that lies to the east of the affected areas, but later InSAR analysis revealed that another previously unknown fracture was responsible for the sequence of shocks.

Tectonic setting

The islands of Indonesia constitute an island arc that is one of the world's most seismically active regions, with high velocity (up to 60 mm (2.4 in) per year) plate movement at the Sunda Trench, and considerable volcanic activity throughout. The south central portion of the island of Java (one of the five largest in the Indonesian archipelago) had been affected by an eruption of Mount Merapi that began prior to the May 27 earthquake, but the Special Region of Yogyakarta has experienced numerous other eruptions, earthquakes, and tsunamis, including the July 2006 Pangandaran earthquake and tsunami that occurred just two months later. Java lies on the Sunda Shelf (and the Sunda microplate) to the north of the Sunda Trench, which is a convergent plate boundary where the Indo-Australian Plate is being subducted under the Eurasian Plate. The subduction zone is characterized by frequent earthquakes and a large number of active volcanoes that influence the regional geography, and due to direct or indirect stress transfer, the offshore plate movement has affected the various onshore faults that are closer to the Special Region of Yogyakarta.^[7]

Earthquake

According to the United States Geological Survey, the M6.3 shock occurred 20 km (12 mi) south-southeast of Yogyakarta at a depth of 10 km (6.2 mi), but other institutions provided source parameters (location and depth) that were not in agreement. No information was present on the extent of the faulting or the direction of propagation, but the shock was unlikely to be related to the eruption of Mount Merapi. The USGS suggested that the focal mechanism was most likely associated with left-lateral slip on a NE–SW trending strike-slip fault, as that is the orientation of the Opak Fault, but this has not been validated. No surface breaks were documented, but the location of the greatest damage that was caused does align with the Opak Fault as a possible source.^[8]

A group of Japanese and Indonesian scientists visited who the area in March 2007 confirmed the lack of surface ruptures, and pointed out that any visible expression of the fault would likely have been rapidly destroyed due to the tropical climate, and have acknowledged the widely-varying locations (and the preference for the Opak Fault) that were reported by the various seismological institutions. Their investigation resulted in a different scenario, with an unknown or newly formed NE–SW trending fault as the origin of the shock, with a projected fault slip of 8 km (5.0 mi) that was based on T. Matsuda's 1975 formula for magnitude/rupture length relationship. Evidence for one of the proposed faults was found in the form of alignment of portions of the Oyo River near the (USGS) epicenter, which is parallel (N°65E) to the Nglipar fault in the southern mountains region. If the shock occurred in this area it could indicate the reactivation of a major fault system. The second proposed fault is further to the east of the first fault and is nearly parallel to the Nfalang and Kembang faults that lie to the north of the Oyo River.^[9]

InSAR analysis

While the densely populated area that saw significant destruction is adjacent to the Opak River Fault, both the USGS and Harvard University placed the epicenter to the east of that fault. Few seismometers were operating in the region, but a group of temporary units that were set up following the mainshock recorded a number of aftershocks that were east of the Opak River Fault and were aligned along a 20 km (12 mi) zone striking N°50E. Due to the ambiguous nature of the available information on the source of the Yogyakarta earthquake, a separate group of Japanese and Indonesian scientists applied one of the first uses of Interferometric synthetic aperture radar (InSAR) to determine the source fault.Several data sets (one captured in April 2006 and another post-earthquake batch from June) were collected from an instrument on board the Advanced Land Observation Satellite and were compared to each other to show potential ground deformation patterns.^[10]

A lack of any dislocation found on the images along the Opak River fault made evident the lack of movement along that fault, and though the aftershocks were occurring at a depth of 8–15 km (5.0–9.3 mi), the deformation was distinct at the surface. The observed ground deformation that was detailed by the differential satellite images and GPS measurements was roughly 10 km (6.2 mi) east of (and parallel to) the Opak River Fault, along a zone that passed through the epicenter as stated by the USGS, and delineated a fault with a strike of N48°E and a dip of 89°. The displacements were not more than 10 cm (3.9 in) and indicated strike-slip motion as well as a component of reverse-slip, and to the west of the Opak River Fault (and closer to the areas of damage) strong ground motion triggered subsidence of volcanic deposits from Mount Merapi.^[10]

Response

Although Tsunami warnings were issued in the early aftermath of the earthquake, the earthquake did not cause any tsunami activity.

Political

President Susilo Bambang Yudhoyono moved the army to the central Java province to aid rescue efforts and the evacuation of victims. A team of Cabinet Ministers was also sent to oversee the operations.

International aid

Many countries and organizations offered foreign aid to the devastated region, but the actual amounts delivered/received often varied from these figures, as in the case of other disasters.

• Japan promised $10 million USD, sent two medical teams and also announced that it will send troops to help out^[11]

• The United Kingdom offered four million pounds ($7,436,800 USD)^[11]

• Saudi Arabia promised $5 million USD, plus food, medical equipment and tents, while the United Arab Emirates and Kuwait each pledged $4 million USD^[11]

• The European Union offered three million euros ($3,800,000 USD)^[12]

• The United States offered $5 million; US military joins relief effort^[13]

• Australia offered 7.5 million Australian dollars ($5,675,000 USD) in aid relief, including 27 member medical team among over 80 personnel^[14]

• China offered $2 million U.S dollars^[15]

• Canada offered two million Canadian dollars ($1.8 million USD)^[16]

• India put forward an aid package worth $2 million.^[17]

• The Church of Jesus Christ of Latter-day Saints (Mormons) donated $1.6 million USD worth of emergency supplies to devastated areas, teaming up with Islamic Relief Worldwide who provided the transportation. In addition, local Indonesian LDS members prepared thousands of meals, hygiene kits, cots, mattresses, and blankets for those requiring medical attention.^[18]

• The Netherlands promised 1 million euros in May plus an extra 10 million euros one month later, Belgium has pledged $832,000, while Norway, France and Italy have offered either medical teams or relief supplies^[11]

• The Red Cross, Red Crescent, OXFAM, Plan International, Jesuit Refugee Service alongside other NGOs and UN agencies, including WFP and UNICEF, provided plastic sheeting, tools and building materials, and cash assistance to the victims.^[12] Japan and Malaysia are to send medical teams to the affected region^[19]

• Singapore offered humanitarian relief assistance in the form of a 35-member Armed Forces Medical Team, a 43-member Civil Defense Force Disaster Assistance and Rescue Team, as well as $50,000 USD worth of emergency supplies^[20]

• The United Nations World Health Organization sent medicines and communications equipment, enough emergency health kits to last 50,000 people three months, and surgical kits for as many as 600 operations^[21]

• Vietnam offered 1,000 tons of rice to Indonesia.^[22]

• The Isle of Man offered £30,000 (US$56,291) to Indonesia^[23]

• King Abdullah II of Jordan ordered to dispatch a plane laden with humanitarian relief to alleviate the suffering of Indonesian earthquake victims that hit Java. The aid included blankets, medicines and other medical equipment.^[24]

• MERCY Malaysia^[25] sent 6 Missions to Yogya the first being sent on the 28th of May 2006. Datuk Dr. Jemilah Mahmood, President of MERCY Malaysia (Mission Leader) and Saiful Nazri, Programme Officer from MERCY Aceh Office went there on the first mission travelling by a special United Nations Humanitarian Air Services (UNHAS) flight from Banda Aceh along with other international organisations based in Aceh and two (2) tonnes of medical supplies contributed by the international agencies from Aceh. The first team had secured ground logistics for the subsequent teams coming in from Kuala Lumpur.

• Eric Edmeades, a Canadian Entrepreneur and author, was traveling in Bali at the time of the quake. He rented a truck, filled it with food, water and medical supplies and—against government advice—went to Jogja to undertake first hand relief work.^[26]

Media

Most international wire services had already had reporters or 'stringers' in the area due to the Mount Merapi eruption to the north of Yogyakarta.

Yogyakarta for many is associated with Borobudur and Prambanan, even though both locations are some distance away from the town. As a result, news stories tend to emphasize the condition of those places. Borobudur suffered no damage whereas Prambanan, which is much closer to the epicentre, has according to reports,^[27] suffered significant damage.

The reporting of the immensity of the problems that were evolving following the earthquake also competed with the crisis in East Timor (Timor Leste) in the media of some countries like Australia and New Zealand.

Reconstruction

The earthquake's shallow depth was a major factor, but the scale of the damage was made worse by failure to meet safe building standards and employ basic earthquake-resistant construction methods, according to FuturArc.^[28] Most homes in the area were built with low-quality materials without structural frames and reinforcing pillars. Many deaths and injuries occurred when buildings and walls collapsed.

The government was slow to implement assistance in reconstructing private houses, leading many homeowners to repair or rebuild their homes either by themselves or with community help. Reconstruction in some areas was aided by relief agencies, like the Red Cross Red Crescent.

Villagers rebuilt their homes with extremely limited resources, using simple affordable materials. They turned to traditional materials, such as bamboo, because of the damage inflicted by collapsing brick walls.

See also

• Bantul
• Sidoarjo mud flow

References

Sources

External links

Wikinews has related news: Earthquake kills thousands in Indonesia

• Magnitude 6.3 - JAVA, INDONESIA – United States Geological Survey
• Indonesia earthquake – CNN Special Report
• An ancient wonder reduced to rubble – The Sydney Morning Herald
• UN health agency rushes aid to quake-struck parts of Indonesia – United Nations
• The Mw 6.3 Java, Indonesia, Earthquake of May 27, 2006 – Earthquake Engineering Research Institute

← Earthquakes in 2006 → January Southern Greece (6.7, Jan 8) Banda Sea (7.6, Jan 26) February Mozambique (7.0, Feb 22) March Borujerd† (6.1, Mar 31) April Kamchatka (6.6–7.6, April) Gujarat (5.5, Apr 6) Tasmania, Australia (2.2, Apr 25) May Tonga (7.9, May 4) 1st Java†‡ (6.2, May 27) July 2nd Java† (7.7, Jul 17) Yanjin (5.2, Jul 22) Tajikistan (4.5, Jul 29) August Mendoza (5.7, Aug 5) September Gulf of Mexico (5.8, Sep 10) October Hawaii (6.7, Oct 15) November Kuril Islands (8.3, Nov 15) December Hengchun (7.1, Dec 26) † indicates earthquake resulting at least 30 deaths ‡ indicates the deadliest earthquake of the year

Earthquakes in Indonesia Historical 1797 Sumatra 1833 Sumatra 1861 Sumatra 20th century 1917 Bali 1931 Southwest Sumatra 1935 Sumatra 1938 Banda Sea 1943 Alahan Panjang 1965 Ceram Sea 1968 Sulawesi 1976 Papua 1977 Sumba 1981 Irian Jaya 1982 Flores 1984 Northern Sumatra 1989 West Papua 1991 Kalabahi 1992 Flores 1994 Liwa 1994 Java 1996 Biak 2000 Sumatra 21st century 2002 Sumatra 2004 Indian Ocean 2005 Sumatra 2006 Banda Sea May 2006 Java 2006 Pangandaran March 2007 Sumatra September 2007 Sumatra 2008 Sulawesi 2009 Papua 2009 Talaud Islands August 2009 Sumatra 2009 West Java September 2009 Sumatra April 2010 Sumatra May 2010 Northern Sumatra 2010 Papua October 2010 Sumatra 2011 Java 2011 Aceh Singkil Regency 2012 Indian Ocean 2013 Aceh Related topics Sunda Trench Great Sumatran fault Sunda megathrust