ESI scale

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The ESI scale ( Environmental Seismic Intensity scale , also ESI 2007 ) is an intensity scale for earthquakes developed by the International Union for Quaternary Research (INQUA) . When it was created, it was called the INQUA scale .

Unlike magnitude scales, e.g. B. the frequently cited Richter scale , intensity scales such as the JMA scale , the EMS scale or the Mercalli scale describe the effects of an earthquake on the surface and can therefore show different strengths for a single earthquake in different locations.

history

The assessment of earthquakes in prehistoric times is very difficult, since neither the magnitude can be measured afterwards, nor is the damage to structures missing, which today serve as the basis for the usual intensity scales . Signs of prehistoric earthquakes are known from the geological examination of sediments . Many of them are still preserved, especially in the geologically recent past of the Quaternary . For this reason, efforts have been made within the scientific community of Quaternary geologists to design an intensity scale for earthquakes that is based exclusively on those effects of an earthquake that can be observed in the natural environment.

In 1999, during the 15th INQUA Congress in Durban, a working group of geologists, seismologists and engineers was set up. The first version of the intensity scale developed by this working group was published as the INQUA scale during the 16th INQUA Congress in Reno and tested until 2007 by applying it to actual earthquake events. The participants at the 17th INQUA Congress in Cairns approved the improved scale, which was officially adopted under the name Environmental Seismic Intensity Scale or ESI 2007 for short .

properties

Like many of today's intensity scales, the ESI scale has twelve levels and consists not only of the scale itself, but also of accompanying guidelines that describe the scientific background and the organization of the scale. The guidelines also contain instructions on how to use them - also in conjunction with the damage-based traditional intensity scales - as well as a description of the key features and the meaning of the technical terms, colors and fonts used.

To enable comparison with the traditional intensity scales, the scale contains three levels (I - III) that have no impact on the environment. The description of these levels is therefore empty.

Table of ESI intensity grades

ESI scale
Main effects Side effects
intensity description Surface
defects and deformations 		Hydrological anomalies Abnormal waves / tsunamis Crevices in the floor Slope movements Tree movements Soil
liquefaction 		Dust clouds Jumping stones Area (km 2 )
I - III no impact on the environment
IV generally noticed - rare and insignificant centimeter millimeter wide very rarely falling rocks, small landslides Branches tremble - - - -
V strong - rare and insignificant decimeter millimeter wide, up to a meter long rarely falling rocks, small landslides Branches and bushes tremble very rare - - -
VI slightly damaging - clearly, mostly temporarily several decimeters millimeter to centimeter wide, several meters long Rock falls and landslides up to 1,000 m 3 z. Sometimes strong tremors of trees and bushes Rare - - -
VII harmful Rare clearly, mostly temporarily meter 5 to 10 centimeters wide, up to a hundred meters long Rock falls and landslides up to 10,000 m 3 strong tremors of trees and bushes rarely, up to 50 cm tall - - 10
VIII severely damaging generally to be observed significant, mostly temporary 1-2 meters 50 centimeters wide, several hundred meters long Rock falls and landslides up to more than 100,000 m 3 strong shaking of trees, occasional uprooting not infrequently, up to 1 m tall in the epicenter in arid areas jumping movement of sand, gravel, small boulders, tree trunks, staying in place 100
IX destructive almost predominantly strong, mostly temporary several meters 100 centimeters wide, several hundred meters long Rock falls and landslides up to more than 1,000,000 m 3 strong shaking and breaking of trees, occasional uprooting often up to 3 m tall often in dry areas jumping movement of small boulders, tree trunks, up to several meters 1,000
X highly destructive mostly strong, partly lasting several meters more than 100 centimeters wide, several hundred meters long Rock falls and landslides up to more than 1,000,000 m 3 strong shaking of trees, many break, isolated uprooting very often, larger areas, subsidence often in dry areas jumping from 2 to 3 m large boulders up to several hundred meters 5,000
XI devastating mostly strong, partly lasting very tall, over 10 meters several meters wide Rock falls and landslides up to more than 1,000,000 m 3 strong shaking of trees, many breaking, often uprooting widespread, subsidence of large areas in dry areas Jumping forward movement of boulders several meters in size possible over long distances 10,000
XII completely devastating mostly strong, partly lasting huge more than 10 meters wide Rock falls and landslides up to more than 1,000,000 m 3 strong shaking of trees, many breaking, often uprooting landscape-
changing 		in dry areas Jumping forward movement of very large boulders possible over long distances 50,000

Detailed description of the features

The characteristics listed in the table above are only brief summaries of the actual effects. They are described in detail in the definition of the ESI scale and include fine gradations of the effects of earthquakes and accompanying phenomena. The associated definitions of the individual effects are explained in more detail below.

The leading letters are assigned the following side effects:

  • a) Hydrological anomalies
  • b) Abnormal waves / tsunamis
  • c) floor crevices
  • d) Slope movements
  • e) Tree movements
  • f) soil liquefaction
  • g) clouds of dust
  • h) jumping stones

Stage IV

Main effects are missing. Side effects are:

a) Small changes in the water level in wells or in the amount of water pouring from springs occur very occasionally and to a limited extent. Very rare small physical and chemical changes or turbidity of the water can be observed from wells or springs, primarily in sources from larger karst - aquifers .

b) Development of a few centimeters high Seiches in closed basins (in lakes and in the sea) - typically in remote area of earthquakes - which generally only levels are detected, often with the naked eye. Abnormal waves are felt by all people in small boats, some in large boats, most of them on the coast. Vibration and sometimes spilling of water in swimming pools has been observed.

c) Occurrence of millimeter-thick hairline cracks in suitable terrain (slopes, mountain ridges) or in certain soil conditions (water-saturated soil, unconsolidated alluvial soil).

d) On steep slopes close to the critical angle and with loose or water-saturated soil, there are occasional rockfalls and small landslides , sometimes as a result of the revitalization of old landslides .

e) Weak trembling of branches.

Stage V

Main effects are missing. Side effects are:

a) Small changes in the water level in wells or in the amount of water poured from springs occur rarely and to a limited extent. Small isolated physical and chemical changes or clouding of the water of lakes, wells or springs are also observed.

b) Development of a few decimeter high lakes in closed basins (in lakes and in the sea) - typically in the remote area of ​​earthquakes - which can sometimes be seen with the naked eye. Abnormal waves a few decimeters high are felt by everyone in boats and on the coast. Water spilling over from swimming pools.

c) Limited occurrence of millimeter-thin cracks with a length of a few centimeters up to one meter with suitable terrain (slopes, mountain ridges) or with certain soil properties (water-saturated soil, unconsolidated alluvial soil).

d) Occasional rockfalls and landslides, not only on steep slopes near the critical angle, mostly with loose deposits or water-saturated soil. Submarine landslides can be triggered, which may create small, abnormal waves on the shores of the lake and ocean.

e) Branches and bushes shake slightly, very rarely dead branches and ripe fruits fall to the ground.

f) Extremely rare observations of soil liquefaction ("boiling" quicksand ) in very limited areas, which are prone to it due to the high groundwater level and suitable soil properties (e.g. alluvial sand).

Stage VI

Main effects are missing. Side effects are:

a) Spatially limited, significant changes in the water level in wells or in the amount of water poured from springs occur. Small physical and chemical changes or clouding of the water of lakes, wells or springs are also observed.

b) Abnormal waves several decimetres high flood very limited areas of the bank. The water spills over from swimming pools, small pools and ponds.

c) If the soil is suitable (water-saturated soil, unconsolidated alluvial soil), the occasional occurrence of millimeter to centimeter wide cracks with a length of up to a few meters that can be open on steep slopes or river banks 1–2 cm. Some small cracks appear in asphalt or paved roads.

d) Rock falls and landslides with a volume of up to 1,000 m 3 , especially on steep slopes and cuttings in the terrain near the critical angle, mostly with loose, water-saturated deposits or heavily weathered and brittle rock. Submarine landslides can be triggered, which occasionally generate small, abnormal waves on the coasts of the lake and sea, mainly recorded by measuring instruments.

e) Branches and bushes shake moderately to strongly, depending on the tree species, the state of health and the fruit load, a few treetops and unstable dead branches break and fall to the ground.

f) Infrequent observations of soil liquefaction ("boiling" quicksand) in very limited areas that are susceptible to this due to the high groundwater level and suitable soil properties (e.g. alluvial sand).

Tier VII

Main effects are observed very rarely, mainly in volcanic areas. Quakes that are very close to the surface in particular create limited surface fractures of a few hundred meters in length and with an offset of a few centimeters.

Side effects affect an area of ​​the order of 10 km 2 .

a) Spatially limited, significant changes in the water level in wells or in the amount of water poured from springs occur temporarily. There is rarely a temporary drying up or formation of small springs. Small physical and chemical changes or cloudiness of the water of lakes, wells or springs are also observed locally.

b) Abnormal waves over three feet high flood limited areas of the bank, damaging or washing away objects of various sizes. The water spills over from small pools and watercourses.

c) If the soil is suitable (water-saturated soil, unconsolidated alluvial soil), cracks 5 to 10 centimeters wide and up to a hundred meters long may appear. Rare cracks up to 1 centimeter wide are observed in dry sand, sandy silt and clay . Centimeter-wide cracks appear in paved or paved roads.

d) Scattered occurrence of landslides, in some cases with a volume of up to 10,000 m 3 , especially on steep slopes and cuttings in the terrain near the critical angle, mostly with loose or water-saturated deposits. Rockfall occurs mainly in steep gorges and cliffs. With dry soil made of sand, sandy silt or clay, the mass movements can reach a volume of up to 100 m 3 . Significant submarine landslides can be triggered, creating abnormal waves on the shores of the sea and ocean that are noticed by people in boats and ports.

e) Trees and bushes tremble strongly, especially in densely populated forests, many tree tops and unstable dead branches break and fall to the ground.

f) Infrequent observations of soil liquefaction ("boiling" quicksand up to 50 cm in diameter) in very limited areas that are susceptible to this due to the high groundwater level and suitable soil properties (e.g. alluvial sand).

Tier VIII

Main effects are rarely observed. In particular, earthquakes very close to the surface, such as those that often occur in volcanic areas, produce limited surface fractures of a few hundred meters in length and with an offset of a few centimeters. In addition, tectonic uplift or subsidence of the earth's surface over a few centimeters can occur.

Side effects affect an area of ​​the order of 100 km 2 .

a) The flow of water or the exit height of springs changes, usually temporarily. Sometimes small springs dry up temporarily or arise. Changes in the water level in wells are observed. Small physical and chemical changes in the water can be detected, mostly changes in temperature. A clouding of the water can be observed in closed lakes, rivers, wells or springs. Gas escapes at some points, mostly containing sulfur.

b) Abnormal waves one to two meters high flood areas close to the banks and damage or wash away objects of various sizes. Erosion and debris deposition occurs along the coast. Some bushes and small, poorly rooted trees were washed away and drifted. Violent spilling of water from small pools and watercourses.

c) If the soil is suitable (water-saturated soil, unconsolidated alluvial soil), cracks up to 50 centimeters wide and up to a hundred meters long occur frequently. In rare cases, cracks up to 1 centimeter wide are observed in hard rock. Decimeter-wide cracks and small pressure waves on the surface arise in asphalt or cobbled streets.

d) Occurrence of small and medium-sized landslides with a volume of 1,000 to 100,000 m 3 in suitable areas, rarely also on flat slopes. In deposits near the critical angle, for example on steep slopes with loose or water-saturated deposits as well as rockfall masses in ravines and on cliffs, landslides can reach a large extent (100,000 to 1,000,000 m 3 ). Landslides can block narrow valleys and lead to the creation of a temporary or permanent reservoir. Fractures, landslides and rockfalls affect river banks, artificial embankments and excavations such as road cuts and quarries in loose sediments and weathered rock. Submarine landslides are often triggered.

e) Trees are shaken vigorously, branches break and fall to the ground, some trees are uprooted, especially on steep slopes.

f) Soil liquefaction can occur frequently in the area of ​​the epicenter if the soil conditions are suitable. Here, "boiling" quicksand up to one meter in diameter occur, as well as apparent fountains in still water, expansion of the surface and subsidence of up to 30 cm. Fissures form parallel to the banks of rivers, lakes, canals and the seashore.

g) In dry areas, clouds of dust can rise in the area of ​​the epicenter.

h) Stones and even small rocks as well as fallen tree trunks can be thrown into the air; their re-impact leaves typical traces in soft ground.

Tier IX

Main effects such as surface fractures of a few kilometers in length and with a displacement of a few centimeters are often observed. In addition, tectonic uplift or subsidence of the earth's surface can occur over a few decimeters.

Side effects affect an area of ​​the order of 1,000 km 2 .

a) The flow of water or the location of springs changes significantly, mostly temporarily. Sometimes medium-sized springs dry up. Temporary changes in the water level in wells are common. Small physical and chemical changes in the water from wells or springs can be detected, mostly changes in temperature. A clouding of the water can be observed in closed lakes, rivers, wells or springs. Gas escapes at some points, mostly containing sulfur. The gas ignites in places and the vegetation near the exit point can burn.

b) Creation of waves several meters high in still and flowing waters, shifting of watercourses in flood plains due to subsidence, appearance and disappearance of small water basins. Depending on the subsea or submarine terrain, tsunamis of several meters in height can arise, flood large areas and pose a threat to humans and animals. Erosion and debris deposition occurs along the entire coast. Underwashing and drifting of bushes and trees.

c) With suitable soil conditions (water-saturated soil, unconsolidated alluvial soil) frequent occurrence of cracks up to 100 centimeters wide and up to several hundred meters in length. Cracks up to 10 centimeters wide are observed in hard rock. Wide cracks and small bumps in the surface appear in asphalt or cobbled streets.

d) Landslides are common, even on flat slopes. In deposits near the critical angle, for example on steep slopes with loose or water-saturated deposits as well as rockfall masses in ravines and on cliffs, landslides can reach a large to very large extent (100,000 to 1,000,000 m 3 ). Landslides can block narrow valleys and lead to the creation of a temporary or permanent reservoir. Fractures, landslides and rockfalls affect river banks, artificial embankments and excavations such as road cuts and quarries in loose sediments and weathered rock. Submarine landslides are often triggered near the coast.

e) Trees are violently shaken, branches and thin tree trunks often break and fall to the ground, some trees are uprooted, especially on steep slopes.

f) Soil liquefaction and the boiling up of water are common, here above all "boiling" quicksand up to three meters in diameter and apparent fountains in still water, often expansion of the surface and settlement of more than 30 cm. Fissures form parallel to the banks of rivers, lakes, canals and the seashore.

g) In dry areas, clouds of dust can rise.

h) Small rocks and fallen tree trunks can be thrown into the air and, depending on their shape and the slope of the terrain, migrate several meters, their re-encounter leaves typical traces in soft ground.

Tier X

Main effects outweigh the side effects. Surface fractures of a few tens of kilometers in length and with an offset of a few centimeters to a few meters are often observed; in volcanic areas, the length of the fractures can be much greater in very shallow earthquakes. Burglaries and elongated hollows develop. In addition, tectonic uplift or subsidence of the earth's surface can occur over a few meters.

Side effects affect an area of ​​the order of 5,000 km 2 .

a) The flow of water or the exit height of many springs changes significantly. Sometimes there is a temporary or complete drying up of some sources. Temporary changes in the water level in wells are common. Partly strong physical and chemical changes in the water from wells or springs can be detected, mostly changes in temperature. A silting up of the water can even be observed in large lakes as well as in rivers, wells or springs. Gas escapes at some points, mostly containing sulfur. The gas ignites in places and the vegetation near the exit point can burn.

b) Formation of waves several meters high even in large still and flowing waters that can leave their bed. Temporary or permanent displacement of watercourses in flood plains due to subsidence; Appearance and disappearance of pools of water. Depending on the subsea or submarine terrain and the formation of the coast, tsunamis of more than 5 meters in height occur, which penetrate several kilometers into the land and can drag small boulders over many meters. Deep erosion occurs along the entire coast, which can significantly alter the coastline. Underwashing and drifting of trees near the banks.

c) With suitable soil conditions (water-saturated soil, unconsolidated alluvial soil), frequent occurrence of open cracks of more than 1 meter with a length of up to several hundred meters. Cracks several decimeters wide are observed in hard rock. Wide cracks and pressure waves on the surface arise in asphalt or cobbled streets.

d) Large landslides and rockfalls larger than 100,000 to 1,000,000 m 3 are common, regardless of the equilibrium of mountain slopes. The landslides can block narrow valleys and thus lead to the creation of a temporary or permanent reservoir. River banks, artificial embankments and the walls of artificial excavations such as street cuttings and quarries collapse. Road and earth embankments can be badly damaged. Submarine landslides are often triggered near the coast.

e) Trees are violently shaken, many branches and tree trunks break and fall to the ground, some trees are uprooted.

f) Soil liquefaction in combination with the surge of water and soil compaction change the appearance of large zones, here mainly sand volcanoes with a diameter of up to six meters occur. Settlements reach a height of more than one meter. Wide and long gaps due to the stretching of the surface are common.

g) Clouds of dust usually rise in dry areas.

h) Rocks with a diameter of more than 2 to 3 m can be thrown into the air and move hundreds of meters above the ground even on a slight slope. This creates typical traces in soft ground.

Stage XI

Main effects predominate. Surface fractures from a few tens of kilometers to over a hundred kilometers in length and with a displacement of a few meters occur. Burglary ditches, pressure ridges and elongated depressions develop, drainage patterns can be changed significantly. In addition, tectonic uplift or subsidence of the earth's surface can occur over many meters.

Side effects affect an area of ​​the order of 10,000 km 2 .

a) The flow of water or the exit height of many springs changes significantly. Often there is a temporary or complete drying up of springs. Temporary changes in the water level in wells are common. Partly strong physical and chemical changes in the water from wells or springs can be detected, mostly changes in temperature. A strong siltation of the water can even be observed in large lakes as well as in rivers, wells or springs. Gas escapes in some places, often containing sulfur. The gas ignites in places and the vegetation near the exit point can burn.

b) Formation of waves several meters high in large still and flowing waters that can leave their bed. Temporary or permanent displacement of watercourses in flood plains due to subsidence; Appearance and disappearance of pools of water. Depending on the subsea or submarine terrain and the formation of the coast, tsunamis of more than 15 meters in height occur, which penetrate several kilometers into the land and can drag meter-sized boulders along over a great distance. Deep erosion occurs along the entire coast, which can significantly alter the coastline. Underwashing and drifting of trees near the banks.

c) With suitable soil conditions (water-saturated soil, unconsolidated alluvial soil) frequent occurrence of cracks several meters open. Cracks up to one meter wide are observed in hard rock. Very wide cracks and strong pressure waves on the surface occur in asphalt or paved roads.

d) Large landslides and rockfalls larger than 100,000 to 1,000,000 m 3 are common, regardless of the state of equilibrium of mountain slopes, and to a lesser extent occur 200 to 300 kilometers from the epicenter. The landslides often block narrow valleys and thus contribute to the creation of a temporary or permanent reservoir. River banks, artificial embankments and the walls of artificial excavations such as street cuttings and quarries collapse. Road and earth embankments can be badly damaged. Large subsea slides are often triggered near the coast.

e) Trees are violently shaken, many branches and tree trunks break and fall to the ground, some trees are uprooted.

f) Soil liquefaction changes the appearance of extensive zones, here in particular many large sand volcanoes occur. Settlements reach a height of several meters. Severe stretching of the surface is common.

g) Clouds of dust rise in dry areas.

h) Rocks with a diameter of several meters can be thrown into the air and move hundreds of meters above the ground even on a slight slope. This creates typical traces in soft ground.

Stage XII

Main effects predominate. Surface fractures with a length of at least a few hundred kilometers and an offset of a few tens of meters occur. Burglary ditches, pressure ridges and elongated depressions develop, drainage patterns can be changed significantly. Changes in the landscape and surface forms caused by the main effects can be extremely extensive and large. Examples of such changes are changes in the coastal height of several meters, the appearance or disappearance of significant landscape elements or lakes, changes in the course of rivers, the formation of waterfalls.

Side effects affect an area of ​​the order of 50,000 km 2 and more.

a) The flow of water or the exit height of many springs changes significantly. Often there is a temporary or complete drying up of springs. Temporary changes in the water level in wells are common. Strong physical and chemical changes in the water from wells or springs can be detected, mostly changes in temperature. A strong siltation of the water can even be observed in large lakes as well as in rivers, wells or springs. Gas escapes in some places, often containing sulfur. The gas ignites in places and the vegetation near the exit point can burn.

b) Creation of gigantic waves in large still and flowing waters that leave their bed. Temporary or permanent displacement of watercourses or even the direction of flow in flood plains due to subsidence and landslides; Appearance and disappearance of large pools of water. Depending on the submarine or submarine terrain and the formation of the coast, tsunamis several tens of meters high occur, which penetrate several kilometers into the land and can drag large boulders over a great distance. Deep erosion occurs along the entire coast, which can completely alter the coastline. Often underwashing and drifting of trees near the bank. All boats are torn from their anchorages and washed away or carried inland over long distances. Anyone outside will be washed away.

c) Cracks more than ten meters open and several kilometers long in water-saturated soil or unconsolidated alluvial soil, cracks more than one meter wide are observed in hard rock.

d) Large landslides and rockfalls larger than 100,000 to 1,000,000 m 3 are common, regardless of the state of equilibrium of mountain slopes, and also occur at a significant size 200 to 300 kilometers from the epicenter. The landslides often block narrow valleys and thus contribute to the creation of a temporary or permanent reservoir. River banks, artificial embankments and the walls of artificial excavations such as street cuttings and quarries collapse. Road and earth embankments can be badly damaged. Very large subsea slides are often triggered near the coast.

e) Trees are violently shaken, many branches and tree trunks break and fall to the ground, some trees are uprooted.

f) Soil liquefaction changes the appearance of extensive zones, here in particular many large sand volcanoes occur. Settlements reach a height of several meters. Very large stretching of the surface is common.

g) Clouds of dust rise in dry areas.

h) Even very large rocks can be thrown into the air and migrate hundreds of meters above the ground even with a slight slope. This creates typical traces in soft ground.

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