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1968 Illinois Earthquake
The 1968 Illinois earthquake (a New Madrid event) was the largest recorded earthquake in the U.S. Midwestern state of Illinois. Striking at 11:02 am on November 9, it measured 5.4 on the Richter scale. Although no fatalities occurred, the event caused considerable structural damage to buildings, including the toppling of chimneys and shaking in Chicago, the region's largest city. The earthquake was one of the most widely felt in U.S. history, largely affecting 23 states over an area of . In studying its cause, scientists discovered the Cottage Grove Fault in the Southern Illinois Basin. Within the region, millions felt the rupture. Reactions to the earthquake varied; some people near the epicenter did not react to the shaking, while others panicked. A future earthquake in the region is extremely likely; in 2005, seismologists and geologists estimated a 90% chance of a magnitude 6–7 tremor before 2055, likely originating in the Wabash Valley seismic zone on the I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoseismal Map
In seismology, an isoseismal map is used to show lines of equally felt seismic intensity, generally measured on the Modified Mercalli scale. Such maps help to identify earthquake epicenters, particularly where no instrumental records exist, such as for historical earthquakes. They also contain important information on ground conditions at particular locations, the underlying geology, radiation pattern of the seismic waves, and the response of different types of buildings. They form an important part of the macroseismic approach, i.e. that part of seismology dealing with noninstrumental data. The shape and size of the isoseismal regions can be used to help determine the magnitude, focal depth, and focal mechanism of an earthquake. History The first known isoseismal map was produced for the 1810 earthquake in Mór in Hungary, and published by Kitaibel and Tomtsányi in 1814. The first, six-level intensity scale was proposed by Egen in 1828 for an earthquake in Rhineland. Robert M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicenter
The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental period of earthquake observation, the epicenter was thought to be the location where the greatest damage occurred, but the subsurface fault rupture may be long and spread surface damage across the entire rupture zone. As an example, in the magnitude 7.9 Denali earthquake of 2002 in Alaska, the epicenter was at the western end of the rupture, but the greatest damage was about away at the eastern end. Focal depths of earthquakes occurring in continental crust mostly range from . Continental earthquakes below are rare whereas in subduction zone earthquakes can originate at depths deeper than . Epicentral distance During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loyola University Chicago
Loyola University Chicago (Loyola or LUC) is a private Jesuit research university in Chicago, Illinois. Founded in 1870 by the Society of Jesus, Loyola is one of the largest Catholic The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide . It is among the world's oldest and largest international institutions, and has played a ... universities in the United States. Its namesake is Saint Ignatius of Loyola. Loyola's professional schools include programs in medicine, nursing, and health sciences anchored by the Loyola University Medical Center. It is Carnegie Classification of Institutions of Higher Education, classified among "R2: Doctoral Universities – High research activity". Comprising thirteen colleges and schools, Loyola offers more than 80 undergraduate and 140 graduate/professional programs and enrolls approximately 17,000 students. Loyola has six campuses across the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contiguous United States
The contiguous United States (officially the conterminous United States) consists of the 48 adjoining U.S. states and the Federal District of the United States of America. The term excludes the only two non-contiguous states, Alaska and Hawaii (also the last ones admitted to the Union), and all other offshore insular areas, such as American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands. The colloquial term "Lower48" is used also, especially in relation to just Alaska (Hawaii is farther south). The related but distinct term continental United States includes Alaska (which is also on the continent of North America but separated from the 48 states by British Columbia and Yukon of Canada), but excludes the Hawaiian Islands and all U.S. territories in the Caribbean and the Pacific. The greatest distance (on a great-circle route) entirely within the contiguous U.S. is 2,802 miles (4,509 km), between Florida and the State of Washington; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1812 New Madrid Earthquake
Year 181 ( CLXXXI) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Aurelius and Burrus (or, less frequently, year 934 '' Ab urbe condita''). The denomination 181 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Imperator Lucius Aurelius Commodus and Lucius Antistius Burrus become Roman Consuls. * The Antonine Wall is overrun by the Picts in Britannia (approximate date). Oceania * The volcano associated with Lake Taupō in New Zealand erupts, one of the largest on Earth in the last 5,000 years. The effects of this eruption are seen as far away as Rome and China. Births * April 2 – Xian of Han, Chinese emperor (d. 234) * Zhuge Liang, Chinese chancellor and regent (d. 234) Deaths * Aelius Aristides, Greek orator and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wabash Valley Fault System
The Wabash Valley Seismic Zone (also known as the Wabash Valley Fault System or Zone) is a tectonic region located in the Midwest of the United States, centered on the valley of the Lower Wabash River, along the state line between southeastern Illinois and southwestern Indiana. Geology The Wabash Valley Seismic Zone consists largely of vertically oriented ("normal") faults deeply buried under layers of sediment. Although the tectonics of the region are still not fully understood and are the subject of ongoing research, these faults are thought by some to be associated with a branch of the New Madrid aulacogen, an old rift zone where the lithosphere actively began to pull apart at perhaps two separate times in the distant past. Present-day GPS measurements show that the region deforms at about 1–2 mm/yr with compression along the Wabash Valley Fault Zone, and extension in SW Indiana. The crust in the area has been weakened by the numerous faults, which remain active sites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault Plane
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Mechanism
The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution. Focal mechanisms are derived from a solution of the moment tensor for the earthquake, which itself is estimated by an analysis of observed seismic waveforms. The focal mechanism can be derived from observing the pattern of "first motions", that is, whether the first arriving P waves break up or down. This method was used before waveforms were recorded and analysed digitally and this method is still used for earthquakes too small for easy moment tensor solution. Focal mechanisms are now mainly derived using semi-automatic analysis of the recorded waveforms. Moment tensor solutions The moment tensor solution is typically displayed graphically using a so-called ''beachball'' diagram. The pattern of en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Wave Magnitude
Body-waves consist of P-waves that are the first to arrive (see seismogram), or S-waves, or reflections of either. Body-waves travel through rock directly. mB scale The original "body-wave magnitude" – mB or mB (uppercase "B") – was developed by and to overcome the distance and magnitude limitations of the scale inherent in the use of surface waves. is based on the P- and S-waves, measured over a longer period, and does not saturate until around M 8. However, it is not sensitive to events smaller than about M 5.5. Use of as originally defined has been largely abandoned, now replaced by the standardized scale. mb scale The mb or mb scale (lowercase "m" and "b") is similar to , but uses only P-waves measured in the first few seconds on a specific model of short-period seismograph. It was introduced in the 1960s with the establishment of the ''World-Wide Standardized Seismograph Network'' (WWSSN); the short period improves detection of smaller events, and better discri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Wave Magnitude
The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This magnitude scale is related to the local magnitude scale proposed by Charles Francis Richter in 1935, with modifications from both Richter and Beno Gutenberg throughout the 1940s and 1950s. It is currently used in People's Republic of China as a national standard (GB 17740-1999) for categorising earthquakes. Recorded magnitudes of earthquakes through the mid 20th century, commonly attributed to Richter, could be either M_s or M_L. Definition The formula to calculate surface wave magnitude is: :M_s = \log_\left(\frac\right)_ + \sigma(\Delta)\,, where A is the maximum particle displacement in surface waves (vector sum of the two horizontal displacements) in μm, T is the corresponding period in s (usually 20 2 seconds), Δ is the epi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Louis University
Saint Louis University (SLU) is a private Jesuit research university with campuses in St. Louis, Missouri, United States, and Madrid, Spain. Founded in 1818 by Louis William Valentine DuBourg, it is the oldest university west of the Mississippi River and the second-oldest Jesuit university in the United States. It is one of 27 member institutions of the Association of Jesuit Colleges and Universities. The university is accredited by the North Central Association of Colleges and Secondary Schools. In the 2021–2022 academic year, SLU had an enrollment of 12,883 students. The student body included 8,138 undergraduate students and 4,745 graduate students that represents all 50 states and 82 countries. The university is classified as a Research II university by the Carnegie Classification of Institutions of Higher Education. For more than 50 years, the university has maintained a campus in Madrid, Spain. The Madrid campus was the first freestanding campus operated by an Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Lake
A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often left behind large deposits of ice in hollows between drumlins or hills. As the ice age ended, these melted to create lakes. This is apparent in the Lake District in Northwestern England where post-glacial sediments are normally between 4 and 6 metres deep. These lakes are often surrounded by drumlins, along with other evidence of the glacier such as moraines, eskers and erosional features such as striations and chatter marks. These lakes are clearly visible in aerial photos of landforms in regions that were glaciated during the last ice age. The formation and characteristics of glacial lakes vary between location and can be classified into glacial erosion lake, ice-bloc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
