An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. The word tremor is also used for non-earthquake seismic rumbling.
An earthquake occurred on January 17, 1995, at 05:46:53 JST in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and had a maximum intensity of 7 on the JMA Seismic Intensity Scale. The tremors lasted for approximately 20 seconds. The focus of the earthquake was located 17 km beneath its epicenter, on the northern end of Awaji Island, 20 km away from the center of the city of Kobe.
Earthquake prediction is a branch of the science of seismology concerned with the specification of the time, location, and magnitude of future earthquakes within stated limits, and particularly "the determination of parameters for the next strong earthquake to occur in a region". Earthquake prediction is sometimes distinguished from earthquake forecasting, which can be defined as the probabilistic assessment of general earthquake hazard, including the frequency and magnitude of damaging earthquakes in a given area over years or decades. Not all scientists distinguish "prediction" and "forecast", but the distinction is useful.
The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately 10 mi (16 km) northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With an magnitude of 6.9 and a maximum Modified Mercalli intensity of IX (Violent), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake until two moderate foreshocks occurred in June 1988 and again in August 1989.
In seismology, an earthquake swarm is a sequence of seismic events occurring in a local area within a relatively short period. The time span used to define a swarm varies, but may be days, months, or years. Such an energy release is different from the situation when a major earthquake is followed by a series of aftershocks: in earthquake swarms, no single earthquake in the sequence is obviously the main shock. In particular, a cluster of aftershocks occurring after a mainshock is not a swarm.
The 1988 Armenian earthquake, also known as the Spitak earthquake, occurred on December 7 at with a surface wave magnitude of 6.8 and a maximum MSK intensity of X (Devastating). The shock occurred in the northern region of Armenia which is vulnerable to large and destructive earthquakes and is part of a larger active seismic belt that stretches from the Alps to the Himalayas. Activity in the area is associated with tectonic plate boundary interaction and the source of the event was slip on a thrust fault just to the north of Spitak. The complex incident ruptured multiple faults, with a strike-slip event occurring shortly after the initiation of the mainshock. Between 25,000 and 50,000 were killed and up to 130,000 were injured.
The Garlock Fault is a left-lateral strike-slip fault running northeast–southwest along the north margins of the Mojave Desert of Southern California, for much of its length along the southern base of the Tehachapi Mountains.
Seconds from Disaster is a US/UK-produced documentary television programme that investigates historically relevant man-made and natural disasters from the 20th and early 21st centuries. Each episode aims to explain a single incident by analyzing the causes and circumstances that ultimately affected the disaster. The program uses re-enactments, interviews, testimonies, and CGI to analyze the sequence of events second-by-second for the audience.
Zero Hour is a documentary-style television series. It aired on History Television in Canada, on the BBC in the United Kingdom, and on The History Channel in the United States. Zero Hour has also aired on Channel Seven in Australia ; on Discovery Channel in Africa, Asia, New Zealand, Brazil, and the Netherlands. The program focuses on retelling the details of tragic man-made disasters which each unfolded in less than an hour.
Mayday, alternatively known as Air Crash Investigation(s) on Seven Network, Australia, New Zealand, South Africa, the United Kingdom, alternatively known as Air Crash: Disaster Revealed on 5Select, India, other Asian countries, and some European countries, and Air Emergency, Air Disasters, and Mayday: Air Disaster in the United States, is a Canadian documentary television program examining air crashes, near-crashes, hijackings, bombings, and other disasters. Mayday uses re-enactments and computer-generated imagery to reconstruct the sequence of events leading up to each disaster. In addition, survivors, aviation experts, retired pilots, and crash investigators are interviewed, to explain how the emergencies came about, how they were investigated, and how they might have been prevented.
On 17 August 1999, a catastrophic magnitude 7.6 earthquake struck the Kocaeli Province of Turkey, causing monumental damage and between 17,127 and 18,373 deaths. Named for the quake's proximity to the northwestern city of İzmit, the earthquake is also commonly referred to as the 17 August Earthquake or the 1999 Gölcük Earthquake. The earthquake occurred at 03:01 local time at a shallow depth of 15 km. A maximum Mercalli intensity of X (Extreme) was observed. The earthquake lasted for 37 seconds, causing seismic damage and is widely remembered as one of the deadliest natural disasters in modern Turkish history.
Blueprint for Disaster is a Canadian documentary television series that premiered in 2004 on Discovery Channel Canada. Produced by Temple Street Productions, the program investigates why and how various disasters have happened. Toronto-based Voice Artist Adrian Bell provided the narration for the first series. The show also aired in the UK under the title Seconds from Disaster. As of 2008, two seasons have been produced.
Critical Situation is an American documentary television series. Produced in conjunction with the National Geographic Channel, the series examined various disasters or violent incidents. It replaced Seconds From Disaster, a similar program with a more forensic approach. The main tagline of the show reads, "This is Situation Critical," or some variation thereof. As of November 2007, 13 episodes have been aired.
Trapped is a six-episode documentary television series that premiered on November 7, 2007 on the National Geographic Channel. Produced in association with the Canadian National Geographic Channel and Cineflix, the program examined various actual incidents or disasters in which victims were trapped on the site.
Shockwave is an American documentary television series that premiered on November 30, 2007, on History. The program compiles video footage and eyewitness accounts to the headline making events and attempts to educate the viewer as to what really happened in a particular event.
Destroyed in Seconds is a half-hour American television series that aired on Discovery Channel. Hosted by Ron Pitts, it features video segments of various things being destroyed fairly quickly such as planes crashing, explosions, sinkholes, boats crashing, fires, race car incidents, floods, factories, etc. The nature of the show closely resembles Real TV. The show uses real video of real events, and commentary explaining the destruction portrayed. Most videos have stock sound effects added. Some of the events seen resulted in fatalities, and all of the events have property damage.
A series of small volcanic earthquakes measuring less than 4.0 on the Richter magnitude scale took place in the sparsely populated Nazko area of the Central Interior of British Columbia, Canada, from October 9, 2007, to June 12, 2008. They occurred just west of Nazko Cone, a small tree-covered cinder cone that last erupted about 7,200 years ago.
In seismology, doublet earthquakes – and more generally, multiplet earthquakes – were originally identified as multiple earthquakes with nearly identical waveforms originating from the same location. They are now characterized as single earthquakes having two main shocks of similar magnitude, sometimes occurring within tens of seconds, but sometimes separated by years. The similarity of magnitude – often within 0.4 magnitude – distinguishes multiplet events from aftershocks, which start at about 1.2 magnitude less than the parent shock and decrease in magnitude and frequency according to known laws.
The 1992 Cape Mendocino earthquakes occurred along the Lost Coast of Northern California on April 25 and 26. The three largest events were the M7.2 thrust mainshock that struck near the unincorporated community of Petrolia midday on April 25 and two primary strike-slip aftershocks measuring 6.5 and 6.6 that followed early the next morning. The sequence encompassed both interplate and intraplate activity that was associated with the Mendocino Triple Junction, a complex system of three major faults that converge near Cape Mendocino. The total number of aftershocks that followed the events exceeded 2,000.
