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{{short description|System of interconnected parts in which the failure of one or few parts can trigger the failure of others}}

{{short description|System of interconnected parts in which the failure of one or few parts can trigger the failure of others}}

[[Image:Networkfailure.gif|thumb|right|An animation demonstrating how a single failure may result in other failures throughout a network.]]

[[Image:Networkfailure.gif|thumb|right|An animation demonstrating how a single failure may result in other failures throughout a network.]]

An animation demonstrating how a single failure may result in other failures throughout a network.

An animation demonstrating how a single failure may result in other failures throughout a network.

A '''cascading failure''' is a process in a system of [[interconnection|interconnected]] parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems.

A '''cascading failure''' is a process in a system of [[interconnection|interconnected]] parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems.

A cascading failure is a process in a system of interconnected parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems.

A cascading failure is a process in a system of interconnected parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems.

Cascading failures may occur when one part of the system fails. When this happens, other parts must then compensate for the failed component. This in turn overloads these nodes, causing them to fail as well, prompting additional nodes to fail one after another.

Cascading failures may occur when one part of the system fails. When this happens, other parts must then compensate for the failed component. This in turn overloads these nodes, causing them to fail as well, prompting additional nodes to fail one after another.

== In power transmission ==

== In power transmission ==

Cascading failure is common in power grids when one of the elements fails (completely or partially) and shifts its load to nearby elements in the system.  Those nearby elements are then pushed beyond their capacity so they become overloaded and shift their load onto other elements.  Cascading failure is a common effect seen in high voltage systems, where a single point of failure (SPF) on a fully loaded or slightly overloaded system results in a sudden spike across all nodes of the system. This surge current can induce the already overloaded nodes into failure, setting off more overloads and thereby taking down the entire system in a very short time.

Cascading failure is common in power grids when one of the elements fails (completely or partially) and shifts its load to nearby elements in the system.  Those nearby elements are then pushed beyond their capacity so they become overloaded and shift their load onto other elements.  Cascading failure is a common effect seen in high voltage systems, where a single point of failure (SPF) on a fully loaded or slightly overloaded system results in a sudden spike across all nodes of the system. This surge current can induce the already overloaded nodes into failure, setting off more overloads and thereby taking down the entire system in a very short time.

级联故障在电网中很常见，当其中一个元件发生故障(完全或部分)并将其负荷转移到系统中附近的元件时。那些附近的元素然后被推动超出他们的能力，所以他们成为超载和转移他们的负载到其他元素。级联故障是高压系统中常见的一种现象，在一个满负荷或轻微超载的系统中，一个单点故障(SPF)会导致系统所有节点突然出现尖峰。这种浪涌电流可能会导致已经超载的节点发生故障，引发更多的过载，从而在很短的时间内使整个系统瘫痪。

级联故障在电网中很常见，当其中一个元件(完全或部分)发生故障并将其负荷转移到系统中附近的元件时，就会推动那些附近的元件超出其容量，从而过载，并将其负荷转移到其他元件上。级联故障在高压系统中也很常见，在一个满载或轻度过载的系统中，一个'''<font color="#ff8000"> 单点故障 Single Point of Failure (SPF)</font>'''会导致系统所有节点突然出现尖峰。这种'''<font color="#ff8000"> 浪涌电流

This failure process cascades through the elements of the system like a ripple on a pond and continues until substantially all of the elements in the system are compromised and/or the system becomes functionally disconnected from the source of its load. For example, under certain conditions a large power grid can collapse after the failure of a single transformer.

This failure process cascades through the elements of the system like a ripple on a pond and continues until substantially all of the elements in the system are compromised and/or the system becomes functionally disconnected from the source of its load. For example, under certain conditions a large power grid can collapse after the failure of a single transformer.

这个故障过程就像池塘上的涟漪一样通过系统的各个元素，并且持续到系统中的所有元素被破坏和/或系统从功能上与其负载的来源断开为止。例如，在某些情况下，一个大型电网可能因为单个变压器的故障而崩溃。

这个故障过程就像池塘上的涟漪一样，在系统的各个元件中层层叠加，直到系统中的所有元件都受到损害和/或系统在功能上与负载源断开。例如，在某些情况下，一个大型电网可能因为单个变压器的故障而崩溃。

Monitoring the operation of a system, in real-time, and judicious disconnection of parts can help stop a cascade.  Another common technique is to calculate a safety margin for the system by computer simulation of possible failures, to establish safe operating levels below which none of the calculated scenarios is predicted to cause cascading failure, and to identify the parts of the network which are most likely to cause cascading failures.

Monitoring the operation of a system, in real-time, and judicious disconnection of parts can help stop a cascade.  Another common technique is to calculate a safety margin for the system by computer simulation of possible failures, to establish safe operating levels below which none of the calculated scenarios is predicted to cause cascading failure, and to identify the parts of the network which are most likely to cause cascading failures.

One of the primary problems with preventing electrical grid failures is that the speed of the control signal is no faster than the speed of the propagating power overload, i.e. since both the control signal and the electrical power are moving at the same speed, it is not possible to isolate the outage by sending a warning ahead to isolate the element.

One of the primary problems with preventing electrical grid failures is that the speed of the control signal is no faster than the speed of the propagating power overload, i.e. since both the control signal and the electrical power are moving at the same speed, it is not possible to isolate the outage by sending a warning ahead to isolate the element.

The question if power grid  failures are correlated have been studied in Daqing Li et al. as well as by Paul DH Hines et al.

The question if power grid  failures are correlated have been studied in Daqing Li et al. as well as by Paul DH Hines et al.

大庆等人已经研究了电网故障是否相关的问题。以及 Paul DH Hines 等人。

电网故障是否具有相关性的问题，李大庆等人以及Paul DH Hines等人都有研究。

=== Examples ===

=== 案例 ===

Cascading failure caused the following [[power outage]]s:

Cascading failure caused the following [[power outage]]s:

Cascading failure caused the following power outages:

Cascading failure caused the following power outages:

级联故障导致下列停电:

级联故障曾导致以下停电:

* [[Northeast blackout of 1965|Blackout in Northeast America in 1965]]

* [[Northeast blackout of 1965|Blackout in Northeast America in 1965]]

* [[1999 Southern Brazil blackout|Blackout in Southern Brazil in 1999]]

* [[1999 Southern Brazil blackout|Blackout in Southern Brazil in 1999]]

* [[Northeast blackout of 2003|Blackout in Northeast America in 2003]]

* [[Northeast blackout of 2003|Blackout in Northeast America in 2003]]

* [[2003 Italy blackout|Blackout in Italy in 2003]]

* [[2003 Italy blackout|Blackout in Italy in 2003]]

* [[2003 London blackout|Blackout in London in 2003]]

* [[2003 London blackout|Blackout in London in 2003]]

* [[2006 European blackout|European Blackout in 2006]]

* [[2006 European blackout|European Blackout in 2006]]

* [[2012 northern India power grid failure|Blackout in Northern India in 2012]]

* [[2012 northern India power grid failure|Blackout in Northern India in 2012]]

* [[2016 South Australian blackout|Blackout in South Australia in 2016]]

* [[2016 South Australian blackout|Blackout in South Australia in 2016]]

* [[2019 Argentina, Paraguay and Uruguay blackout|Blackout in southeast South America in 2019]]

* [[2019 Argentina, Paraguay and Uruguay blackout|Blackout in southeast South America in 2019]]

== In computer networks ==

== In computer networks ==

Cascading failures can also occur in computer networks (such as the Internet) in which network traffic is severely impaired or halted to or between larger sections of the network, caused by failing or disconnected hardware or software. In this context, the cascading failure is known by the term cascade failure. A cascade failure can affect large groups of people and systems.

Cascading failures can also occur in computer networks (such as the Internet) in which network traffic is severely impaired or halted to or between larger sections of the network, caused by failing or disconnected hardware or software. In this context, the cascading failure is known by the term cascade failure. A cascade failure can affect large groups of people and systems.

计算机网络(例如互联网)也可能发生级联故障，由于硬件或软件故障或断开，网络通信严重受损，或在网络较大部分之间停止。在这种背景下，级联失效这一术语被称为级联失效。级联故障可以影响大量的人员和系统。

级联故障也可能发生在计算机网络(如因特网)中，由于硬件或软件的故障或断开，导致网络中较大部分的网络通信严重受损或停止。在这种情况下，级联故障被称为术语级联故障。级联故障会影响到大批人员和系统。

The cause of a cascade failure is usually the overloading of a single, crucial router or node, which causes the node to go down, even briefly. It can also be caused by taking a node down for maintenance or upgrades. In either case, traffic is routed to or through another (alternative) path. This alternative path, as a result, becomes overloaded, causing it to go down, and so on. It will also affect systems which depend on the node for regular operation.

The cause of a cascade failure is usually the overloading of a single, crucial router or node, which causes the node to go down, even briefly. It can also be caused by taking a node down for maintenance or upgrades. In either case, traffic is routed to or through another (alternative) path. This alternative path, as a result, becomes overloaded, causing it to go down, and so on. It will also affect systems which depend on the node for regular operation.

级联故障的原因通常是一个单一的、关键的路由器或节点的超载，这会导致节点宕机，甚至是短暂的宕机。它也可能是由于为了维护或升级而关闭一个节点引起的。在这两种情况下，流量都被路由到或通过另一条(可选)路径。结果，这个替代路径变得超载，导致它下降，等等。它还会影响依赖于节点进行常规操作的系统。

级联故障的原因通常是一个单个关键的路由器或节点的超载，导致节点宕机或短暂地宕机。它也可能是由于为了维护或升级而关闭一个节点引起的。在这两种情况下，流量都被路由到或通过另一条(替代)路径。结果，这条替代路径变得过载，导致它宕机，等等。它还会影响依赖该节点正常运行的系统。

=== Symptoms ===

=== Symptoms ===

The symptoms of a cascade failure include: packet loss and high network latency, not just to single systems, but to whole sections of a network or the internet. The high latency and packet loss is caused by the nodes that fail to operate due to congestion collapse, which causes them to still be present in the network but without much or any useful communication going through them. As a result, routes can still be considered valid, without them actually providing communication.

The symptoms of a cascade failure include: packet loss and high network latency, not just to single systems, but to whole sections of a network or the internet. The high latency and packet loss is caused by the nodes that fail to operate due to congestion collapse, which causes them to still be present in the network but without much or any useful communication going through them. As a result, routes can still be considered valid, without them actually providing communication.

级联故障的症状包括: 数据包丢失和高网络延迟，不仅仅是对单个系统，而是对整个网络或互联网部分。高延迟和数据包丢失是由于网络拥塞崩溃导致的节点无法正常运行所造成的，这使得它们仍然存在于网络中，但是没有多少或任何有用的通信通过它们。因此，路由仍然可以被认为是有效的，而实际上它们并没有提供通信。

级联故障的症状包括: 数据包丢失和高网络延迟，不仅仅是对单个系统，而是对整个网络或互联网部分。高延迟和数据包丢失是由于网络拥塞崩溃导致节点无法正常运行，这使得它们仍然存在于网络中，但是没有太多或任何有用的通信通过它们。因此，路由仍然可被认为是有效的，而实际上它们并没有提供通信。

If enough routes go down because of a cascade failure, a complete section of the network or internet can become unreachable. Although undesired, this can help speed up the recovery from this failure as connections will time out, and other nodes will give up trying to establish connections to the section(s) that have become cut off, decreasing load on the involved nodes.

If enough routes go down because of a cascade failure, a complete section of the network or internet can become unreachable. Although undesired, this can help speed up the recovery from this failure as connections will time out, and other nodes will give up trying to establish connections to the section(s) that have become cut off, decreasing load on the involved nodes.

A common occurrence during a cascade failure is a walking failure, where sections go down, causing the next section to fail, after which the first section comes back up. This ripple can make several passes through the same sections or connecting nodes before stability is restored.

A common occurrence during a cascade failure is a walking failure, where sections go down, causing the next section to fail, after which the first section comes back up. This ripple can make several passes through the same sections or connecting nodes before stability is restored.

 

=== History ===

=== History ===

Cascade failures are a relatively recent development, with the massive increase in traffic and the high interconnectivity between systems and networks. The term was first applied in this context in the late 1990s by a Dutch IT professional and has slowly become a relatively common term for this kind of large-scale failure.

Cascade failures are a relatively recent development, with the massive increase in traffic and the high interconnectivity between systems and networks. The term was first applied in this context in the late 1990s by a Dutch IT professional and has slowly become a relatively common term for this kind of large-scale failure.

 

=== Example ===

=== Example ===

Network failures typically start when a single network node fails. Initially, the traffic that would normally go through the node is stopped. Systems and users get errors about not being able to reach hosts. Usually, the redundant systems of an ISP respond very quickly, choosing another path through a different backbone. The routing path through this alternative route is longer, with more hops and subsequently going through more systems that normally do not process the amount of traffic suddenly offered.

Network failures typically start when a single network node fails. Initially, the traffic that would normally go through the node is stopped. Systems and users get errors about not being able to reach hosts. Usually, the redundant systems of an ISP respond very quickly, choosing another path through a different backbone. The routing path through this alternative route is longer, with more hops and subsequently going through more systems that normally do not process the amount of traffic suddenly offered.

This can cause one or more systems along the alternative route to go down, creating similar problems of their own.

This can cause one or more systems along the alternative route to go down, creating similar problems of their own.

Also, related systems are affected in this case. As an example, DNS resolution might fail and what would normally cause systems to be interconnected, might break connections that are not even directly involved in the actual systems that went down. This, in turn, may cause seemingly unrelated nodes to develop problems, that can cause another cascade failure all on its own.

Also, related systems are affected in this case. As an example, DNS resolution might fail and what would normally cause systems to be interconnected, might break connections that are not even directly involved in the actual systems that went down. This, in turn, may cause seemingly unrelated nodes to develop problems, that can cause another cascade failure all on its own.

In December 2012, a partial loss (40%) of Gmail service occurred globally, for 18 minutes. This loss of service was caused by a routine update of load balancing software which contained faulty logic—in this case, the error was caused by logic using an [https://arstechnica.com/information-technology/2012/12/why-gmail-went-down-google-misconfigured-chromes-sync-server/ inappropriate all instead of the more appropriate some.] The cascading error was fixed by fully updating a single node in the network instead of partially updating all nodes at one time.

In December 2012, a partial loss (40%) of Gmail service occurred globally, for 18 minutes. This loss of service was caused by a routine update of load balancing software which contained faulty logic—in this case, the error was caused by logic using an [https://arstechnica.com/information-technology/2012/12/why-gmail-went-down-google-misconfigured-chromes-sync-server/ inappropriate all instead of the more appropriate some.] The cascading error was fixed by fully updating a single node in the network instead of partially updating all nodes at one time.

2012年12月，全球范围内发生了部分 Gmail 服务中断(40%) ，时间长达18分钟。这种服务的丢失是由于包含错误逻辑的负载平衡软件的例行更新造成的---- 在这种情况下，错误是由于逻辑使用了[ https://arstechnica.com/information-technology/2012/12/why-gmail-went-down-google-misconfigured-chromes-sync-server/不恰当的所有而不是更适当的一些]通过对网络中单个节点的全面更新而不是对所有节点的部分更新，修复了级联错误。

2012年12月，Gmail服务在全球范围内出现了部分损失(40%)，持续了18分钟。这次服务损失是由包含错误逻辑的负载平衡软件的例行更新引起的--在这种情况下，该错误是由使用[https://arstechnica.com/information-technology/2012/12/why-gmail-went-down-google-misconfigured-chromes-sync-server/ 不合适的all而不是更合适的some]的逻辑引起的。通过完全更新网络中的一个节点，而不是一次部分更新所有节点，修复了级联错误。

== Cascading structural failure ==

== Cascading structural failure ==

Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members.  In the case of the [[Hyatt Regency walkway collapse]], a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a [[zipper]]). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate [[factor of safety]] and/or alternate load paths to prevent this type of mechanical cascade failure.<ref name="petroski">{{cite book| title=To Engineer Is Human: The Role of Failure in Structural Design| first=Henry| last=Petroski| year=1992| isbn=978-0-679-73416-1| publisher=Vintage| place=| url-access=registration| url=https://archive.org/details/toengineerishuma00petr}}</ref>

Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members.  In the case of the [[Hyatt Regency walkway collapse]], a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a [[zipper]]). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate [[factor of safety]] and/or alternate load paths to prevent this type of mechanical cascade failure.<ref name="petroski">{{cite book| title=To Engineer Is Human: The Role of Failure in Structural Design| first=Henry| last=Petroski| year=1992| isbn=978-0-679-73416-1| publisher=Vintage| place=| url-access=registration| url=https://archive.org/details/toengineerishuma00petr}}</ref>

Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members.  In the case of the Hyatt Regency walkway collapse, a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a zipper). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate factor of safety and/or alternate load paths to prevent this type of mechanical cascade failure.

Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members.  In the case of the Hyatt Regency walkway collapse, a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a zipper). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate factor of safety and/or alternate load paths to prevent this type of mechanical cascade failure.

某些承重结构与分立的结构组件可以受到“拉链效应” ，其中一个单一的结构成员的失败增加了对相邻成员的负荷。在倒塌的情况下，当一个垂直悬挂杆失效时，一个悬挂人行道(由于施工错误已经过度受力)失效，导致相邻的杆超载，相继失效(即:。像拉链一样)。一座可能发生这种破坏的桥梁被称为断裂临界桥梁，许多桥梁的垮塌都是由单一部分的破坏引起的。正确设计的结构使用足够的安全系数和/或交替加载路径，以防止这种类型的机械叶栅失效。

某些具有离散结构构件的承重结构可能会出现 "拉链效应"，即单个结构构件的失效会增加相邻构件的荷载。 在凯悦酒店人行道坍塌事件中，当单根垂直悬杆失效时，悬空的人行道（由于施工中的错误，人行道已经过度受力）失效，使相邻的悬杆超载，相邻的悬杆依次失效（像拉链一样）。一座可能发生这种破坏的桥梁被称为断裂临界桥梁，许多桥梁的坍塌都是由单一部件的故障引起的。正确设计的结构使用足够的安全系数和/或交替的荷载路径来防止这种类型的机械级联失效。

== Other examples ==

== Other examples ==

=== Biology ===

=== Biology ===

[[Biochemical cascade]]s exist in biology, where a small reaction can have system-wide implications. One negative example is [[ischemic cascade]], in which a small [[ischemia|ischemic]] attack releases [[toxin]]s which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in [[stroke]] patients to minimize the damage.

[[Biochemical cascade]]s exist in biology, where a small reaction can have system-wide implications. One negative example is [[ischemic cascade]], in which a small [[ischemia|ischemic]] attack releases [[toxin]]s which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in [[stroke]] patients to minimize the damage.

Biochemical cascades exist in biology, where a small reaction can have system-wide implications. One negative example is ischemic cascade, in which a small ischemic attack releases toxins which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in stroke patients to minimize the damage.

Biochemical cascades exist in biology, where a small reaction can have system-wide implications. One negative example is ischemic cascade, in which a small ischemic attack releases toxins which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in stroke patients to minimize the damage.

In the study of extinction, sometimes the extinction of one species will cause many other extinctions to happen. Such a species is known as a keystone species.

In the study of extinction, sometimes the extinction of one species will cause many other extinctions to happen. Such a species is known as a keystone species.

=== Electronics ===

=== Electronics ===

Another example is the [[Cockcroft–Walton generator]], which can also experience cascade failures wherein one failed [[diode]] can result in all the diodes failing in a fraction of a second.

Another example is the [[Cockcroft–Walton generator]], which can also experience cascade failures wherein one failed [[diode]] can result in all the diodes failing in a fraction of a second.

Another example is the Cockcroft–Walton generator, which can also experience cascade failures wherein one failed diode can result in all the diodes failing in a fraction of a second.

Another example is the Cockcroft–Walton generator, which can also experience cascade failures wherein one failed diode can result in all the diodes failing in a fraction of a second.

Yet another example of this effect in a scientific experiment was the implosion in 2001 of several thousand fragile glass photomultiplier tubes used in the Super-Kamiokande experiment, where the shock wave caused by the failure of a single detector appears to have triggered the implosion of the other detectors in a chain reaction.

Yet another example of this effect in a scientific experiment was the implosion in 2001 of several thousand fragile glass photomultiplier tubes used in the Super-Kamiokande experiment, where the shock wave caused by the failure of a single detector appears to have triggered the implosion of the other detectors in a chain reaction.

{{main|Systemic risk}} {{main|Cascades in financial networks}}

{{main|Systemic risk}} {{main|Cascades in financial networks}}

In [[finance]], the risk of cascading failures of financial institutions is referred to as ''[[systemic risk]]:'' the failure of one financial institution may cause other financial institutions (its [[Counterparty|counterparties]]) to fail, cascading throughout the system.<ref name="HuangVodenska2013">{{cite journal|last1=Huang|first1=Xuqing|last2=Vodenska|first2=Irena|last3=Havlin|first3=Shlomo|last4=Stanley|first4=H. Eugene|title=Cascading Failures in Bi-partite Graphs: Model for Systemic Risk Propagation|journal=Scientific Reports|volume=3|pages=1219|year=2013|issn=2045-2322|doi=10.1038/srep01219|pmid=23386974|pmc=3564037|arxiv=1210.4973|bibcode=2013NatSR...3E1219H}}</ref>

In [[finance]], the risk of cascading failures of financial institutions is referred to as ''[[systemic risk]]:'' the failure of one financial institution may cause other financial institutions (its [[Counterparty|counterparties]]) to fail, cascading throughout the system.<ref name="HuangVodenska2013">{{cite journal|last1=Huang|first1=Xuqing|last2=Vodenska|first2=Irena|last3=Havlin|first3=Shlomo|last4=Stanley|first4=H. Eugene|title=Cascading Failures in Bi-partite Graphs: Model for Systemic Risk Propagation|journal=Scientific Reports|volume=3|pages=1219|year=2013|issn=2045-2322|doi=10.1038/srep01219|pmid=23386974|pmc=3564037|arxiv=1210.4973|bibcode=2013NatSR...3E1219H}}</ref>

In finance, the risk of cascading failures of financial institutions is referred to as systemic risk: the failure of one financial institution may cause other financial institutions (its counterparties) to fail, cascading throughout the system.

In finance, the risk of cascading failures of financial institutions is referred to as systemic risk: the failure of one financial institution may cause other financial institutions (its counterparties) to fail, cascading throughout the system.

Institutions that are believed to pose systemic risk are deemed either "[[too big to fail]]" (TBTF) or "too interconnected to fail" (TICTF), depending on why they appear to pose a threat.

Institutions that are believed to pose systemic risk are deemed either "[[too big to fail]]" (TBTF) or "too interconnected to fail" (TICTF), depending on why they appear to pose a threat.

Institutions that are believed to pose systemic risk are deemed either "too big to fail" (TBTF) or "too interconnected to fail" (TICTF), depending on why they appear to pose a threat.

Institutions that are believed to pose systemic risk are deemed either "too big to fail" (TBTF) or "too interconnected to fail" (TICTF), depending on why they appear to pose a threat.

那些被认为构成系统性风险的机构要么被视为“太大而不能倒”(TBTF) ，要么被视为“太相关而不能倒”(TICTF) ，这取决于它们为什么似乎构成了威胁。

那些被认为构成系统性风险的机构要么被视为“太大而不能倒”(TBTF) ，要么被视为“太相关而不能倒闭”(TICTF) ，这取决于它们为什么会构成威胁。

Note however that systemic risk is not due to individual institutions per se, but due to the interconnections. For detailed models in economics and finance, see Elliott et al. (2014) and Acemoglu et al. (2015).

Note however that systemic risk is not due to individual institutions per se, but due to the interconnections. For detailed models in economics and finance, see Elliott et al. (2014) and Acemoglu et al. (2015).

A related (though distinct) type of cascading failure in finance occurs in the stock market, exemplified by the 2010 Flash Crash.

A related (though distinct) type of cascading failure in finance occurs in the stock market, exemplified by the 2010 Flash Crash.

== Interdependent cascading failures ==

== Interdependent cascading failures ==

[[File:Interdependent_relationship_among_different_infrastructures.tif|thumb|right|Fig. 1: Illustration of the interdependent relationship among different infrastructures]]

[[File:Interdependent_relationship_among_different_infrastructures.tif|thumb|right|Fig. 1: Illustration of the interdependent relationship among different infrastructures]]

Fig. 1: Illustration of the interdependent relationship among different infrastructures

Fig. 1: Illustration of the interdependent relationship among different infrastructures

图。1: 说明不同基础设施之间的相互依存关系

图1: 不同基础设施之间的相互依存关系的说明

[[File:Schematic_demonstration_of_first-_and_second-order_percolation_transitions.tif|thumb|right|Fig. 2. Schematic demonstration of first- and second-order percolation transitions. In the second-order case, the giant component is continuously approaching zero at the percolation threshold p = p_c. In the first-order case, the giant component approaches zero discontinuously]]

[[File:Schematic_demonstration_of_first-_and_second-order_percolation_transitions.tif|thumb|right|Fig. 2. Schematic demonstration of first- and second-order percolation transitions. In the second-order case, the giant component is continuously approaching zero at the percolation threshold p = p_c. In the first-order case, the giant component approaches zero discontinuously]]

Fig. 2. Schematic demonstration of first- and second-order percolation transitions. In the second-order case, the giant component is continuously approaching zero at the percolation threshold p = p_c. In the first-order case, the giant component approaches zero discontinuously

Fig. 2. Schematic demonstration of first- and second-order percolation transitions. In the second-order case, the giant component is continuously approaching zero at the percolation threshold p = p_c. In the first-order case, the giant component approaches zero discontinuously

图。2.一阶和二阶渗流过渡的示意图演示。在二阶情况下，在逾渗阈值 p = p _ c 处，巨分量连续接近零。在一阶情况下，巨分量不连续地趋近于零

图2： 一阶和二阶渗流过渡的示意图。在二阶情况下，'''<font color="#32CD32">最大连通分支 giant component</font>'''在渗流阈值p=p_c时不断接近零。在一阶情况下，最大连通分支不连续地接近零。

Diverse infrastructures such as water supply, transportation, fuel and power stations are coupled together and depend on each other for functioning, see Fig. 1.  Owing to this coupling, interdependent networks are extremely sensitive to random failures, and in particular to targeted attacks, such that a failure of a small fraction of nodes in one network can triger an iterative cascade of failures in several interdependent networks. Electrical blackouts frequently result from a cascade of failures between interdependent networks, and the problem has been dramatically exemplified by the several large-scale blackouts that have occurred in recent years. Blackouts are a fascinating demonstration of the important role played by the dependencies between networks. For example, the 2003 Italy blackout resulted in a widespread failure of the railway network, health care systems, and financial services and, in addition, severely influenced the telecommunication networks. The partial failure of the communication system in turn further impaired the electrical grid management system, thus producing a positive feedback on the power grid. This example emphasizes how inter-dependence can significantly magnify the damage in an interacting network system. A framework to study the cascading failures between coupled networks  based on percolation theory was developed recently.<ref>{{cite journal|last=S. V. Buldyrev|first=R. Parshani, G. Paul, H. E. Stanley, S. Havlin|title=Catastrophic cascade of failures in interdependent networks|journal=Nature|year=2010|volume=464|pages=1025–8|doi=10.1038/nature08932|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&year=*&match=all|pmid=20393559|issue=7291

Diverse infrastructures such as water supply, transportation, fuel and power stations are coupled together and depend on each other for functioning, see Fig. 1.  Owing to this coupling, interdependent networks are extremely sensitive to random failures, and in particular to targeted attacks, such that a failure of a small fraction of nodes in one network can triger an iterative cascade of failures in several interdependent networks. Electrical blackouts frequently result from a cascade of failures between interdependent networks, and the problem has been dramatically exemplified by the several large-scale blackouts that have occurred in recent years. Blackouts are a fascinating demonstration of the important role played by the dependencies between networks. For example, the 2003 Italy blackout resulted in a widespread failure of the railway network, health care systems, and financial services and, in addition, severely influenced the telecommunication networks. The partial failure of the communication system in turn further impaired the electrical grid management system, thus producing a positive feedback on the power grid. This example emphasizes how inter-dependence can significantly magnify the damage in an interacting network system. A framework to study the cascading failures between coupled networks  based on percolation theory was developed recently.<ref>{{cite journal|last=S. V. Buldyrev|first=R. Parshani, G. Paul, H. E. Stanley, S. Havlin|title=Catastrophic cascade of failures in interdependent networks|journal=Nature|year=2010|volume=464|pages=1025–8|doi=10.1038/nature08932|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&year=*&match=all|pmid=20393559|issue=7291

各种各样的基础设施，如供水、交通、燃料和发电站是相互联系、相互依存的。1.由于这种耦合，相互依赖的网络对随机故障，特别是对有针对性的攻击极为敏感，以至于一个网络中一小部分节点的故障可以导致几个相互依赖的网络中一连串的故障。电力中断往往是由于相互依赖的网络之间的一连串故障造成的，最近几年发生的几次大规模停电就是这个问题的最好例证。停电是网络间依赖关系所扮演的重要角色的有趣演示。例如，2003年意大利大停电导致铁路网、卫生保健系统和金融服务大面积瘫痪，此外还严重影响了电信网络。通信系统的局部故障反过来又进一步损害了电网管理系统，从而对电网产生正反馈。这个例子强调了相互依赖如何能够显著地放大交互网络系统中的损害。基于渗流理论，最近发展了一个研究耦合网络之间级联故障的框架。1 = r.在相互依赖的网络中灾难性的级联故障 | 杂志 = 自然 | 年 = 2010 | 卷 = 464 | 页 = 1025-8 | doi = 10.1038/nature08932 | url =  http://Havlin.biu.ac.il/publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&year=*&match=all|pmid=20393559|issue=7291

诸如供水、运输、燃料和发电站等多种基础设施都是耦合在一起的，并相互依赖着运行，见图1。 由于这种耦合，相互依存的网络对随机故障，特别是对有针对性的攻击极为敏感，因此，一个网络中一小部分节点的故障就会导致几个相互依存的网络中出现一连串的故障。电气停电经常是由相互依赖的网络之间的故障级联造成的，近年来发生的几次大规模停电事件就极大地说明了这个问题。停电是网络之间的依存关系所起的重要作用的一个引人入胜的证明。例如，2003年意大利大停电导致铁路网、医疗系统、金融服务大面积瘫痪，此外，还严重影响了电信网络。通信系统的部分故障又进一步损害了电网管理系统，从而对电网产生了正反馈。这个例子强调了在一个相互影响的网络系统中，相互依赖性是如何显著放大损害的。基于'''<font color="#ff8000"> 渗流理论 Percolation Theory</font>'''，最近发展了一个研究耦合网络之间级联故障的框架。1 = r.在相互依赖的网络中灾难性的级联故障 | 杂志 = 自然 | 年 = 2010 | 卷 = 464 | 页 = 1025-8 | doi = 10.1038/nature08932 | url =  http://Havlin.biu.ac.il/publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&year=*&match=all|pmid=20393559|issue=7291

 

|arxiv=1012.0206|bibcode=2010Natur.464.1025B}}</ref> The cascading failures can lead to abrupt collapse compare to percolation in a single network where the breakdown of the network is continuous, see Fig. 2.

|arxiv=1012.0206|bibcode=2010Natur.464.1025B}}</ref> The cascading failures can lead to abrupt collapse compare to percolation in a single network where the breakdown of the network is continuous, see Fig. 2.

|arxiv=1012.0206|bibcode=2010Natur.464.1025B}}</ref> The cascading failures can lead to abrupt collapse compare to percolation in a single network where the breakdown of the network is continuous, see Fig. 2.

|arxiv=1012.0206|bibcode=2010Natur.464.1025B}}</ref> The cascading failures can lead to abrupt collapse compare to percolation in a single network where the breakdown of the network is continuous, see Fig. 2.

Cascading failures in spatially embedded systems have been

Cascading failures in spatially embedded systems have been

Cascading failures in spatially embedded systems have been

Cascading failures in spatially embedded systems have been

shown to lead to extreme vulnerability.<ref name="BashanBerezin2013">{{cite journal|last1=Bashan|first1=Amir|last2=Berezin|first2=Yehiel|last3=Buldyrev|first3=Sergey V.|last4=Havlin|first4=Shlomo|title=The extreme vulnerability of interdependent spatially embedded networks|journal=Nature Physics|year=2013|issn=1745-2473|doi=10.1038/nphys2727|volume=9|issue=10|pages=667–672|arxiv=1206.2062|bibcode=2013NatPh...9..667B}}</ref> For the dynamic process of cascading failures see ref.<ref>{{Cite journal|last=Zhou|first=D.|last2=Bashan|first2=A.|last3=Cohen|first3=R.|last4=Berezin|first4=Y.|last5=Shnerb|first5=N.|last6=Havlin|first6=S.|date=2014|title=Simultaneous first- and second-order percolation transitions in interdependent networks|url=|journal=Phys. Rev. E|volume=90|issue=1|pages=012803|bibcode=2014PhRvE..90a2803Z|doi=10.1103/PhysRevE.90.012803|pmid=25122338|arxiv=1211.2330}}</ref> A model for repairing failures in order to avoid cascading failures was developed by Di Muro et al.<ref>{{Cite journal|last=Di Muro|first=M. A.|last2=La Rocca|first2=C. E.|last3=Stanley|first3=H. E.|last4=Havlin|first4=S.|last5=Braunstein|first5=L. A.|date=2016-03-09|title=Recovery of Interdependent Networks|journal=Scientific Reports|language=En|volume=6|issue=1|pages=22834|doi=10.1038/srep22834|pmid=26956773|pmc=4783785|issn=2045-2322|arxiv=1512.02555|bibcode=2016NatSR...622834D}}</ref>

shown to lead to extreme vulnerability.<ref name="BashanBerezin2013">{{cite journal|last1=Bashan|first1=Amir|last2=Berezin|first2=Yehiel|last3=Buldyrev|first3=Sergey V.|last4=Havlin|first4=Shlomo|title=The extreme vulnerability of interdependent spatially embedded networks|journal=Nature Physics|year=2013|issn=1745-2473|doi=10.1038/nphys2727|volume=9|issue=10|pages=667–672|arxiv=1206.2062|bibcode=2013NatPh...9..667B}}</ref> For the dynamic process of cascading failures see ref.<ref>{{Cite journal|last=Zhou|first=D.|last2=Bashan|first2=A.|last3=Cohen|first3=R.|last4=Berezin|first4=Y.|last5=Shnerb|first5=N.|last6=Havlin|first6=S.|date=2014|title=Simultaneous first- and second-order percolation transitions in interdependent networks|url=|journal=Phys. Rev. E|volume=90|issue=1|pages=012803|bibcode=2014PhRvE..90a2803Z|doi=10.1103/PhysRevE.90.012803|pmid=25122338|arxiv=1211.2330}}</ref> A model for repairing failures in order to avoid cascading failures was developed by Di Muro et al.<ref>{{Cite journal|last=Di Muro|first=M. A.|last2=La Rocca|first2=C. E.|last3=Stanley|first3=H. E.|last4=Havlin|first4=S.|last5=Braunstein|first5=L. A.|date=2016-03-09|title=Recovery of Interdependent Networks|journal=Scientific Reports|language=En|volume=6|issue=1|pages=22834|doi=10.1038/srep22834|pmid=26956773|pmc=4783785|issn=2045-2322|arxiv=1512.02555|bibcode=2016NatSR...622834D}}</ref>

shown to lead to extreme vulnerability. For the dynamic process of cascading failures see ref. A model for repairing failures in order to avoid cascading failures was developed by Di Muro et al.

shown to lead to extreme vulnerability. For the dynamic process of cascading failures see ref. A model for repairing failures in order to avoid cascading failures was developed by Di Muro et al.

 

== Model for overload cascading failures ==

== Model for overload cascading failures ==

A model for cascading failures due to overload propagation is the Motter–Lai model.<ref>{{Cite journal|last=Motter|first=A. E.|last2=Lai|first2=Y. C.|date=2002|title=Cascade-based attacks on complex networks|url=|journal=Phys. Rev. E|volume=66|issue=6 Pt 2|pages=065102|doi=10.1103/PhysRevE.66.065102|pmid=12513335|bibcode=2002PhRvE..66f5102M|arxiv=cond-mat/0301086}}</ref> The tempo-spatial propagation of such failures have been studied by Jichang Zhao et al.<ref>{{Cite journal|last=Zhao|first=J.|last2=Li|first2=D.|last3=Sanhedrai|first3=H.|last4=Cohen|first4=R.|last5=Havlin|first5=S.|date=2016|title=Spatio-temporal propagation of cascading overload failures in spatially embedded networks|url=|journal=Nature Communications|volume=7|pages=10094|bibcode=2016NatCo...710094Z|doi=10.1038/ncomms10094|pmid=26754065|pmc=4729926}}</ref>

A model for cascading failures due to overload propagation is the Motter–Lai model.<ref>{{Cite journal|last=Motter|first=A. E.|last2=Lai|first2=Y. C.|date=2002|title=Cascade-based attacks on complex networks|url=|journal=Phys. Rev. E|volume=66|issue=6 Pt 2|pages=065102|doi=10.1103/PhysRevE.66.065102|pmid=12513335|bibcode=2002PhRvE..66f5102M|arxiv=cond-mat/0301086}}</ref> The tempo-spatial propagation of such failures have been studied by Jichang Zhao et al.<ref>{{Cite journal|last=Zhao|first=J.|last2=Li|first2=D.|last3=Sanhedrai|first3=H.|last4=Cohen|first4=R.|last5=Havlin|first5=S.|date=2016|title=Spatio-temporal propagation of cascading overload failures in spatially embedded networks|url=|journal=Nature Communications|volume=7|pages=10094|bibcode=2016NatCo...710094Z|doi=10.1038/ncomms10094|pmid=26754065|pmc=4729926}}</ref>

A model for cascading failures due to overload propagation is the Motter–Lai model. The tempo-spatial propagation of such failures have been studied by Jichang Zhao et al.

A model for cascading failures due to overload propagation is the Motter–Lai model. The tempo-spatial propagation of such failures have been studied by Jichang Zhao et al.

过载传播引起的连锁故障模型是 Motter-Lai 模型。赵等人研究了这类故障的时空传播特性。

过载传播导致的级联故障的模型是Motter-Lai模型。赵继昌等人对这种故障的速度空间传播进行了研究。

== See also ==

== See also ==

{{div col}}

{{div col}}

* [[Power outage|Blackouts]]

* [[Power outage|Blackouts]]

* [[Brittle system]]

* [[Brittle system]]

* [[Butterfly effect]]

* [[Butterfly effect]]

* [[Byzantine failure]]

* [[Byzantine failure]]

* [[Cascading rollback]]

* [[Cascading rollback]]

* [[Chain reaction]]

* [[Chain reaction]]

* [[Chaos theory]]

* [[Chaos theory]]

* [[Cache stampede]]

* [[Cache stampede]]

* [[Congestion collapse]]

* [[Congestion collapse]]

* [[Domino effect]]

* [[Domino effect]]

* [[For Want of a Nail (proverb)]]

* [[For Want of a Nail (proverb)]]

* [[Interdependent networks]]

* [[Interdependent networks]]

* [[Kessler Syndrome]]

* [[Kessler Syndrome]]

* [[Percolation theory]]

* [[Percolation theory]]

* [[Progressive collapse]]

* [[Progressive collapse]]

* [[Virtuous circle and vicious circle]]

* [[Virtuous circle and vicious circle]]

* [[Wicked problem]]

* [[Wicked problem]]

{{div col end}}

{{div col end}}

== References ==

== References ==

{{reflist}}

{{reflist}}

== Further reading ==

== Further reading ==

* {{cite web  

* {{cite web