Question: What was the magnitude of the earthquake that affected the city where the national flag is hoisted on January 26th in September 2011?

full_context: Document 1: Delhi Republic Day parade: To mark the importance of the Republic Day, every year a grand parade is held in the capital, New Delhi, from the Raisina Hill Rashtrapati Bhavan (the President's residence), along the Rajpath, past India Gate. Prior to its commencement, the Prime Minister lays a floral wreath at the Amar Jawan Jyoti, a memorial to fallen soldiers at the India Gate at one end of Rajpath, which is followed by two minutes silence in the memory of fallen soldiers. It is a solemn reminder of the sacrifice of the martyrs who died for the country in the freedom movement and the succeeding wars for the defence of sovereignty of their country. Thereafter he / she reaches the main dais at Rajpath to join other dignitaries, subsequently the President arrives along with the chief guest of the occasion. They are escorted on horseback by the President's Bodyguard.
Document 2: Istanbul: Istanbul is near the North Anatolian Fault, close to the boundary between the African and Eurasian Plates. This fault zone, which runs from northern Anatolia to the Sea of Marmara, has been responsible for several deadly earthquakes throughout the city's history. Among the most devastating of these seismic events was the 1509 earthquake, which caused a tsunami that broke over the walls of the city and killed more than 10,000 people. More recently, in 1999, an earthquake with its epicenter in nearby İzmit left 18,000 people dead, including 1,000 people in Istanbul's suburbs. The people of Istanbul remain concerned that an even more catastrophic seismic event may be in the city's near future, as thousands of structures recently built to accommodate Istanbul's rapidly increasing population may not have been constructed properly. Seismologists say the risk of a 7.6-magnitude or greater earthquake striking Istanbul by 2030 is more than 60 percent.
Document 3: Rajpath: Rajpath (constructed as and formerly named King's Way during the period of the British Raj) is a ceremonial boulevard in New Delhi, India, that runs from Rashtrapati Bhavan on Raisina Hill through Vijay Chowk and India Gate, National War Memorial (India) to National Stadium, Delhi. The avenue is lined on both sides by huge lawns, canals and rows of trees. Considered to be one of the most important roads in India, it is where the annual Republic Day parade takes place on 26 January. Janpath (meaning "People's Way") crosses the road. Rajpath runs in east-west direction. Roads from Connaught Place, the financial centre of Delhi, run into Rajpath from north.
Document 4: New Delhi: The Rajpath which was built similar to the Champs-Élysées in Paris is the ceremonial boulevard for the Republic of India located in New Delhi. The annual Republic Day parade takes place here on 26 January.
Document 5: Independence Day (India): Independence Day is annually celebrated on 15 August, as a national holiday in India commemorating the nation's independence from the United Kingdom on 15 August 1947, the UK Parliament passed the Indian Independence Act 1947 transferring legislative sovereignty to the Indian Constituent Assembly. India still retained King George VI as head of state until its transition to full republican constitution. India attained independence following the Independence Movement noted for largely nonviolent resistance and civil disobedience led by the Indian National Congress (INC). Independence coincided with the partition of India, in which the British India was divided along religious lines into the Dominions of India and Pakistan; the partition was accompanied by violent riots and mass casualties, and the displacement of nearly 15 million people due to religious violence. On 15 August 1947, the Prime Minister, Jawaharlal Nehru raised the Indian national flag above the Lahori Gate of the Red Fort in Delhi. On each subsequent Independence Day, the prime minister customarily raises the flag and gives an address to the nation.
Document 6: Seattle: Due to its location in the Pacific Ring of Fire, Seattle is in a major earthquake zone. On February 28, 2001, the magnitude 6.8 Nisqually earthquake did significant architectural damage, especially in the Pioneer Square area (built on reclaimed land, as are the Industrial District and part of the city center), but caused only one fatality. Other strong quakes occurred on January 26, 1700 (estimated at 9 magnitude), December 14, 1872 (7.3 or 7.4), April 13, 1949 (7.1), and April 29, 1965 (6.5). The 1965 quake caused three deaths in Seattle directly, and one more by heart failure. Although the Seattle Fault passes just south of the city center, neither it nor the Cascadia subduction zone has caused an earthquake since the city's founding. The Cascadia subduction zone poses the threat of an earthquake of magnitude 9.0 or greater, capable of seriously damaging the city and collapsing many buildings, especially in zones built on fill.
Document 7: Delhi Republic Day parade: The Chief Guest of the function is the President of India who arrives escorted by the Presidential Body Guard (PBG), a cavalry unit. When the President arrives, the PBG commander asks the unit to give the National Salute, which is followed by playing of the Indian National Anthem, Jana Gana Mana, by the Army developed the ceremony of display by the massed bands in which Military Bands, Pipe and Drum Bands, Buglers and Trumpeters from various Army Regiments besides bands from the Navy and Air Force take part which play popular tunes like Abide With Me, Mahatma Gandhi's favourite hymn, and Saare Jahan Se Achcha at the end.
Document 8: New Delhi: New Delhi lies on several fault lines and thus experiences frequent earthquakes, most of them of mild intensity. There has, however, been a spike in the number of earthquakes in the last six years, most notable being a 5.4 magnitude earthquake in 2015 with its epicentre in Nepal, a 4.7-magnitude earthquake on 25 November 2007, a 4.2-magnitude earthquake on 7 September 2011, a 5.2-magnitude earthquake on 5 March 2012, and a swarm of twelve earthquakes, including four of magnitudes 2.5, 2.8, 3.1, and 3.3, on 12 November 2013.
Document 9: April 2015 Nepal earthquake: Thousands of houses were destroyed across many districts of the country, with entire villages flattened, especially those near the epicenter.
Document 10: New Delhi: New Delhi is a cosmopolitan city due to the multi-ethnic and multi-cultural presence of the vast Indian bureaucracy and political system. The city's capital status has amplified the importance of national events and holidays. National events such as Republic Day, Independence Day and Gandhi Jayanti (Gandhi's birthday) are celebrated with great enthusiasm in New Delhi and the rest of India. On India's Independence Day (15 August) the Prime Minister of India addresses the nation from the Red Fort. Most Delhiites celebrate the day by flying kites, which are considered a symbol of freedom. The Republic Day Parade is a large cultural and military parade showcasing India's cultural diversity and military might.
Document 11: Independence Day (India): Independence Day of India The National Flag of India hoisted at the Red Fort in Delhi; hoisted flags are a common sight on Independence Day. Also called स्वतंत्रता दिवस Observed by India Type National Significance Commemorates the independence of India Celebrations Flag hoisting, parade, fireworks, singing patriotic songs and the National Anthem Jana Gana Mana, speech by the Prime Minister of India and President of India Date 15 August Frequency Annual First time 15th August 1947 Related to Republic Day
Document 12: Southern California: Many faults are able to produce a magnitude 6.7+ earthquake, such as the San Andreas Fault, which can produce a magnitude 8.0 event. Other faults include the San Jacinto Fault, the Puente Hills Fault, and the Elsinore Fault Zone. The USGS has released a California Earthquake forecast which models Earthquake occurrence in California.
Document 13: Republic Day (India): The main Republic Day celebration is held in the national capital, New Delhi, at the Rajpath before the President of India. On this day, ceremonious parades take place at the Rajpath, which are performed as a tribute to India; its unity in diversity and rich cultural heritage.
Document 14: Houston: The Houston area has over 150 active faults (estimated to be 300 active faults) with an aggregate length of up to 310 miles (500 km), including the Long Point–Eureka Heights fault system which runs through the center of the city. There have been no significant historically recorded earthquakes in Houston, but researchers do not discount the possibility of such quakes having occurred in the deeper past, nor occurring in the future. Land in some areas southeast of Houston is sinking because water has been pumped out of the ground for many years. It may be associated with slip along the faults; however, the slippage is slow and not considered an earthquake, where stationary faults must slip suddenly enough to create seismic waves. These faults also tend to move at a smooth rate in what is termed "fault creep", which further reduces the risk of an earthquake.
Document 15: New Delhi: With a total area of 42.7 km2 (16.5 sq mi), New Delhi forms a small part of the Delhi metropolitan area. Because the city is located on the Indo-Gangetic Plain, there is little difference in elevation across the city. New Delhi and surrounding areas were once a part of the Aravalli Range; all that is left of those mountains is the Delhi Ridge, which is also called the Lungs of Delhi. While New Delhi lies on the floodplains of the Yamuna River, it is essentially a landlocked city. East of the river is the urban area of Shahdara. New Delhi falls under the seismic zone-IV, making it vulnerable to earthquakes.
ground_truth: 4.2-magnitude
sub_queries: where is the national flag hoisted on 26 january Answer: New Delhi
What was the magnitude of the earthquake that affected New Delhi on September 2011? Answer: 4.2-magnitude