An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities; the seismicity, or seismic activity, of an area is the frequency and size of earthquakes experienced over a period of time. The word tremor is used for non-earthquake seismic rumbling. At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground; when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can trigger landslides, volcanic activity. In its most general sense, the word earthquake is used to describe any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused by rupture of geological faults, but by other events such as volcanic activity, mine blasts, nuclear tests.
An earthquake's point of initial rupture is called its hypocenter. The epicenter is the point at ground level directly above the hypocenter. Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane; the sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior. Once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface; this continues until the stress has risen sufficiently to break through the asperity allowing sliding over the locked portion of the fault, releasing the stored energy. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface, cracking of the rock, thus causing an earthquake.
This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior. There are three main types of fault, all of which may cause an interplate earthquake: normal and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas.
Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip. Reverse faults those along convergent plate boundaries are associated with the most powerful earthquakes, megathrust earthquakes, including all of those of magnitude 8 or more. Strike-slip faults continental transforms, can produce major earthquakes up to about magnitude 8. Earthquakes associated with normal faults are less than magnitude 7. For every unit increase in magnitude, there is a thirtyfold increase in the energy released. For instance, an earthquake of magnitude 6.0 releases 30 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 900 times more energy than a 5.0 magnitude of earthquake. An 8.6 magnitude earthquake releases the same amount of energy as 10,000 atomic bombs like those used in World War II. This is so because the energy released in an earthquake, thus its magnitude, is proportional to the area of the fault that ruptures and the stress drop.
Therefore, the longer the length and the wider the width of the faulted area, the larger the resulting magnitude. The topmost, brittle part of the Earth's crust, the cool slabs of the tectonic plates that are descending down into the hot mantle, are the only parts of our planet which can store elastic energy and release it in fault ruptures. Rocks hotter than about 300 °C flow in response to stress; the maximum observed lengths of ruptures and mapped faults are 1,000 km. Examples are the earthquakes in Chile, 1960; the longest earthquake ruptures on strike-slip faults, like the San Andreas Fault, the North Anatolian Fault in Turkey and the Denali Fault in Alaska, are about half to one third as long as the lengths along subducting plate margins, those along normal faults are shorter. The most important parameter controlling the maximum earthquake magnitude on a fault is however not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins, the dip angle of the rupture plane is shallow about 10 de
The Appian Way is one of the earliest and strategically most important Roman roads of the ancient republic. It connected Rome to Brindisi, in southeast Italy, its importance is indicated by its common name, recorded by Statius: Appia longarum... regina viarum "the Appian Way the queen of the long roads" The road is named after Appius Claudius Caecus, the Roman censor who began and completed the first section as a military road to the south in 312 BC during the Samnite Wars. The Appian Way was used as a main route for military supplies since its construction for that purpose in 312 B. C; the Appian Way was the first long road built to transport troops outside the smaller region of greater Rome. The few roads outside the early city were Etruscan and went to Etruria. By the late Republic, the Romans had expanded over most of Italy and were masters of road construction, their roads began at Rome, where the master itinerarium, or list of destinations along the roads, was located, extended to the borders of their domain — hence the expression, "All roads lead to Rome".
Romans had an affinity for the people of Campania, like themselves, traced their backgrounds to the Etruscans. The Samnite Wars were instigated by the Samnites when Rome attempted to ally itself with the city of Capua in Campania; the Italic speakers in Latium had long ago been incorporated into the Roman state. They were responsible for changing Rome from a Etruscan to a Italic state. Dense populations of sovereign Samnites remained in the mountains north of Capua, just north of the Greek city of Neapolis. Around 343 BC, Rome and Capua attempted to form a first step toward a closer unity; the Samnites reacted with military force. Between Capua and Rome lay the Pontine Marshes, a swamp infested with malaria. A tortuous coastal road wound between Ostia at the mouth of the Neapolis; the Via Latina followed its ancient and scarcely more accessible path along the foothills of Monti Laziali and Monti Lepini, which are visible towering over the former marsh. In the First Samnite War the Romans found they could not support or resupply troops in the field against the Samnites across the marsh.
A revolt of the Latin League drained their resources further. They settled with Samnium; the Romans were only biding their time. The first answer was the colonia, a "cultivation" of settlers from Rome, who would maintain a permanent base of operations; the Second Samnite War erupted when Rome attempted to place a colony at Cales in 334 and again at Fregellae in 328 on the other side of the marshes. The Samnites, now a major power after defeating the Greeks of Tarentum, occupied Neapolis to try to ensure its loyalty; the Neapolitans appealed to Rome, which expelled the Samnites from Neapolis. In 312 BC, Appius Claudius Caecus became, he was of the gens Claudia, who were patricians descended from the Sabines taken into the early Roman state. He had been given the name of the founding ancestor of the gens, he was a populist. A man of inner perspicacity, in the years of success he was said to have lost his outer vision and thus acquired the name caecus, "blind". Without waiting to be told what to do by the Senate, Appius Claudius began bold public works to address the supply problem.
An aqueduct secured the water supply of the city of Rome. By far the best known project was the road, which ran across the Pontine Marshes to the coast northwest of Naples, where it turned north to Capua. On it, any number of fresh troops could be sped to the theatre of operations, supplies could be moved en masse to Roman bases without hindrance by either enemy or terrain, it is no surprise that, after his term as censor, Appius Claudius became consul twice, subsequently held other offices, was a respected consultant to the state during his years. The road achieved its purpose; the outcome of the Second Samnite War was at last favorable to Rome. In a series of blows the Romans reversed their fortunes, bringing Etruria to the table in 311 BC, the year of their revolt, Samnium in 304; the road was the main factor that allowed them to concentrate their forces with sufficient rapidity and to keep them adequately supplied, wherein they became a formidable opponent. The main part of the Appian Way was started and finished in 312 BC.
The road began as a leveled dirt road upon which mortar were laid. Gravel was laid upon this, topped with tight fitting, interlocking stones to provide a flat surface; the historian Procopius said that the stones fit together so securely and that they appeared to have grown together rather than to have been fitted together. The road was cambered in the middle and had ditches on either side of the road which were protected by retaining walls; the road began in the Forum Romanum, passed through the Servian Wall at the porta Capena, went through a cutting in the clivus Martis, left the city. For this stretch of the road, the builders used the via Latina; the building of the Aurelian Wall centuries required the placing of another gate, the Porta Appia. Outside of Rome the new via Appia went through well-to-do suburbs along the via Norba, the ancient track to the Alban hills, where Norba was situated; the road at the time was a via a gravel road. The Romans built a high-quality road, with layers of cemented stone over a layer of small stones, drainage ditches on either side, low retaining walls on sunken portions, dirt pathways for sidewalks.
The via Appia is believed to have be
Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; the chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. Aluminium is remarkable for its low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the aerospace industry and important in transportation and building industries, such as building facades and window frames; the oxides and sulfates are the most useful compounds of aluminium. Despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals; because of these salts' abundance, the potential for a biological role for them is of continuing interest, studies continue.
Of aluminium isotopes, only 27Al is stable. This is consistent with aluminium having an odd atomic number, it is the only aluminium isotope that has existed on Earth in its current form since the creation of the planet. Nearly all the element on Earth is present as this isotope, which makes aluminium a mononuclidic element and means that its standard atomic weight equates to that of the isotope; the standard atomic weight of aluminium is low in comparison with many other metals, which has consequences for the element's properties. All other isotopes of aluminium are radioactive; the most stable of these is 26Al and therefore could not have survived since the formation of the planet. However, 26Al is produced from argon in the atmosphere by spallation caused by cosmic ray protons; the ratio of 26Al to 10Be has been used for radiodating of geological processes over 105 to 106 year time scales, in particular transport, sediment storage, burial times, erosion. Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.
The remaining isotopes of aluminium, with mass numbers ranging from 21 to 43, all have half-lives well under an hour. Three metastable states are known, all with half-lives under a minute. An aluminium atom has 13 electrons, arranged in an electron configuration of 3s23p1, with three electrons beyond a stable noble gas configuration. Accordingly, the combined first three ionization energies of aluminium are far lower than the fourth ionization energy alone. Aluminium can easily surrender its three outermost electrons in many chemical reactions; the electronegativity of aluminium is 1.61. A free aluminium atom has a radius of 143 pm. With the three outermost electrons removed, the radius shrinks to 39 pm for a 4-coordinated atom or 53.5 pm for a 6-coordinated atom. At standard temperature and pressure, aluminium atoms form a face-centered cubic crystal system bound by metallic bonding provided by atoms' outermost electrons; this crystal system is shared by some other metals, such as copper. Aluminium metal, when in quantity, is shiny and resembles silver because it preferentially absorbs far ultraviolet radiation while reflecting all visible light so it does not impart any color to reflected light, unlike the reflectance spectra of copper and gold.
Another important characteristic of aluminium is its low density, 2.70 g/cm3. Aluminium is a soft, lightweight and malleable with appearance ranging from silvery to dull gray, depending on the surface roughness, it is nonmagnetic and does not ignite. A fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation; the yield strength of pure aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has stiffness of steel, it is machined, cast and extruded. Aluminium atoms are arranged in a face-centered cubic structure. Aluminium has a stacking-fault energy of 200 mJ/m2. Aluminium is a good thermal and electrical conductor, having 59% the conductivity of copper, both thermal and electrical, while having only 30% of copper's density. Aluminium is capable of superconductivity, with a superconducting critical temperature of 1.2 kelvin and a critical magnetic field of about 100 gauss.
Aluminium is the most common material for the fabrication of superconducting qubits. Aluminium's corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that forms when the bare metal is exposed to air preventing further oxidation, in a process termed passivation; the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts in the presence of dissimilar metals. In acidic solutions, aluminium reacts with water to form hydrogen, in alkaline ones to form aluminates—protective passivation under these conditions is negligible; because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium. However, because
Travertine is a form of limestone deposited by mineral springs hot springs. Travertine has a fibrous or concentric appearance and exists in white, cream-colored, rusty varieties, it is formed by a process of rapid precipitation of calcium carbonate at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites and other speleothems, it is used in Italy and elsewhere as a building material. Travertine is a terrestrial sedimentary rock, formed by the precipitation of carbonate minerals from solution in ground and surface waters, and/or geothermally heated hot-springs. Similar deposits formed from ambient-temperature water are known as tufa; the word'travertine' is derived from the Italian travertino, itself a derivation of the Latin tiburtinus'of Tibur'. Its namesake is the origin of Tivoli, a district near Rome. Modern travertine is formed from geothermally heated supersaturated alkaline waters, with raised pCO2. On emergence, waters degas CO2 due to the lower atmospheric pCO2, resulting in an increase in pH.
Since carbonate solubility decreases with increased pH, precipitation is induced. Precipitation may be enhanced by factors leading to a reduction in pCO2, for example increased air-water interactions at waterfalls may be important, as may photosynthesis. Precipitation may be enhanced by evaporation in some springs. Both calcite and aragonite are found in hot spring travertines; when pure and fine, travertine is white, but it is brown to yellow due to impurities. Travertine may precipitate out directly onto rock and other inert materials as in Pamukkale or Mammoth Hot Springs for example. In Italy, well-known travertine quarries exist in Tivoli and Guidonia Montecelio, where the most important quarries since Ancient Roman times can be found; the Guidonia quarry has major historic value, as it was one of the quarries where Gian Lorenzo Bernini selected material from which to build the famous Colonnade of St. Peter's Square in Rome in 1656-1667. Michaelangelo chose travertine as the material for the external ribs of the dome of St Peter's Basilica.
Travertine derives its name from the former town, known as Tibur in ancient Roman times. The ancient name for the stone was lapis tiburtinus, meaning tibur stone, corrupted to travertino. Detailed studies of the Tivoli and Guidonia travertine deposits revealed diurnal and annual rhythmic banding and laminae, which have potential use in geochronology. Cascades of natural lakes formed behind travertine dams can be seen in Pamukkale, a UNESCO World Heritage Site. Other places with such cascades include Huanglong in Sichuan Province of China, the Mammoth Hot Springs in the US, Egerszalók in Hungary, Abbass Abad, Atash Kooh, Badab-e Surt in Iran, Band-i-Amir in Afghanistan, Lagunas de Ruidera, Hierve el Agua, Oaxaca and Semuc Champey, Guatemala. In Central Europe's last post-glacial palaeoclimatic optimum, huge deposits of tufa formed from karst springs. Important geotopes are found at the Swabian Alb in valleys at the foremost northwest ridge of the cuesta. On a smaller scale, these karst processes are still working.
Travertine has been an important building material since the Middle Ages. Travertine has formed sixteen huge, natural dams in a valley in Croatia known as Plitvice Lakes National Park. Clinging to moss and rocks in the water, the travertine has built up over several millennia to form waterfalls up to 70 m in height. In the U. S. the most well-known place for travertine formation is Yellowstone National Park, where the geothermal areas are rich in travertine deposits. Wyoming has travertines in Hot Springs State Park in Thermopolis. Oklahoma has two parks dedicated to this natural wonder. Turner Falls, the tallest waterfall in Oklahoma, is a 77 feet cascade of spring water flowing over a travertine cave. Honey Creek creates miles of travertine shelves both up and downstream. Many small waterfalls upstream in the dense woods repeat the travertine-formation effect; the city of Davis has made it a tourist attraction. Another travertine resource is in Oklahoma, 10 miles east of Turner Falls. Travertine Creek flows through a spring-water nature preserve within the boundaries of the Chickasaw National Recreation Area.
In Texas, the city of Austin and its surrounding "Hill Country" to the south is built on limestone. The area has many travertine formations, such as those found at Gorman Falls within Colorado Bend State Park, the nature preserve known as Hamilton Pool, the West Cave Preserve, Krause Springs in Spicewood. Hanging Lake in Glenwood Canyon in Colorado has aqua blue water. Rifle Falls State Park in Colorado features a triple waterfall over a travertine dam. In Arizona, on the south side of the Grand Canyon there is the Havasupai Reservation. Flowing through it is Havasu Creek, which has extensive travertine deposits. Three major waterfalls, Navajo Falls, Havasu Falls, Mooney Falls, are all located downstream from the town of Supai. There are numerous smaller cataracts formed by travertine dams; these features are located about 2 miles from Supai Village, are accessible by foot or horseback. In Iceland, the Hva
Nero was the last Roman emperor of the Julio-Claudian dynasty. He became Claudius' heir and successor. Like Claudius, Nero became emperor with the consent of the Praetorian Guard. Nero's mother, Agrippina the Younger, was implicated in Claudius' death and Nero's nomination as emperor, she dominated Nero's early life and decisions. Five years into his reign, he had her murdered. During the early years of his reign, Nero was content to be guided by his mother, his tutor Lucius Annaeus Seneca and his Praetorian prefect, Sextus Afranius Burrus; as time passed, he started to play a more active and independent role in government and foreign policy. During his reign, the redoubtable general Corbulo conducted a successful war and negotiated peace with the Parthian Empire, his general Suetonius Paulinus crushed a major revolt in Britain, led by the Iceni Queen Boudica. The Bosporan Kingdom was annexed to the empire, the First Jewish–Roman War began. Nero focused much of his attention on diplomacy and the cultural life of the empire, ordering theatres built and promoting athletic games.
He made public appearances as an actor, poet and charioteer. In the eyes of traditionalists, this undermined the dignity and authority of his person and office, his extravagant, empire-wide program of public and private works was funded by a rise in taxes, much resented by the middle and upper classes. Various plots against his life were revealed. In 68 AD Vindex, governor of the Gaulish territory Gallia Lugdunensis, rebelled, he was supported by the governor of Hispania Tarraconensis. Vindex's revolt failed in its immediate aim, but Nero fled Rome when Rome's discontented civil and military authorities chose Galba as emperor, he committed suicide on June 9, 68 AD, when he learned that he had been tried in absentia and condemned to death as a public enemy, making him the first Roman Emperor to commit suicide. His death ended the Julio-Claudian dynasty, sparking a brief period of civil wars known as the Year of the Four Emperors. Nero's rule is associated with tyranny and extravagance. Most Roman sources, such as Suetonius and Cassius Dio, offer overwhelmingly negative assessments of his personality and reign.
Suetonius tells that many Romans believed that the Great Fire of Rome was instigated by Nero to clear the way for his planned palatial complex, the Domus Aurea. According to Tacitus he was said to have seized Christians as scapegoats for the fire and burned them alive motivated not by public justice but by personal cruelty; some modern historians question the reliability of the ancient sources on Nero's tyrannical acts. A few sources paint Nero in a more favorable light. There is evidence of his popularity among the Roman commoners in the eastern provinces of the Empire, where a popular legend arose that Nero had not died and would return. At least three leaders of short-lived, failed rebellions presented themselves as "Nero reborn" to enlist popular support. Nero was born Lucius Domitius Ahenobarbus on 15 December 37 AD in Antium, he was the only son of Agrippina the Younger. His maternal grandparents were Agrippina the Elder, he was Augustus' great-great grandson, descended from the first Emperor's only daughter, Julia.
The ancient biographer Suetonius, critical of Nero's ancestors, wrote that Augustus had reproached Nero's grandfather for his unseemly enjoyment of violent gladiator games. According to Jürgen Malitz, Suetonius tells that Nero's father was known to be "irascible and brutal", that both "enjoyed chariot races and theater performances to a degree not befitting their position."Nero's father, died in 40. A few years before his death, Domitius had been involved in a political scandal that, according to Malitz, "could have cost him his life if Tiberius had not died in the year 37." In the previous year, Nero's mother Agrippina had been caught up in a scandal of her own. Caligula's beloved sister Drusilla had died and Caligula began to feel threatened by his brother-in-law Marcus Aemilius Lepidus. Agrippina, suspected of adultery with her brother-in-law, was forced to carry the funerary urn after Lepidus' execution. Caligula banished his two surviving sisters and Julia Livilla, to a remote island in the Mediterranean Sea.
According to The Oxford Encyclopedia of Ancient Greece and Rome, Agrippina was exiled for plotting to overthrow Caligula. Nero's inheritance was taken from him and he was sent to live with his paternal aunt Domitia Lepida, the mother of Claudius' third wife Valeria Messalina. Caligula's reign lasted from 37 until 41, he died from multiple stab wounds in January of 41 after being ambushed by his own Praetorian Guard on the Palatine Hill. Claudius succeeded Caligula as Emperor. Agrippina became his fourth wife. By February 49, she had persuaded Claudius to adopt her son Nero. After Nero's adoption, "Claudius" became part of his name: Nero Claudius Caesar Drusus Germanicus. Claudius had gold coins issued to mark the adoption. Classics professor Josiah Osgood has written that "the coins, through their distribution and imagery alike, showed that a new Leader was in the making." David Shotter noted that, despite events in Rome, Nero's step-brother Britannicus was more prominent in provincial coinages during the early 50s.
Nero formally entered public life as an adult in 51 AD—he was around 14 years old. When he turned 16, Nero married Claudius' daughter (
Tuff known as volcanic tuff, is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is compacted into a solid rock in a process called consolidation. Tuff is sometimes erroneously called "tufa" when used as construction material, but properly speaking, tufa is a limestone precipitated from groundwater. Rock that contains greater than 50% tuff is considered tuffaceous. Tuff is a soft rock, so it has been used for construction since ancient times. Since it is common in Italy, the Romans used it for construction; the Rapa Nui people used it to make most of the moai statues in Easter Island. Tuff can be classified as either sedimentary or igneous rock, they are studied in the context of igneous petrology, although they are sometimes described using sedimentological terms. The material, expelled in a volcanic eruption can be classified into three types: Volcanic gases, a mixture made of steam, carbon dioxide, a sulfur compound Lava, the name of magma when it emerges and flows over the surface Tephra, chunks of solid material of all shapes and sizes ejected and thrown through the airTephra is made when magma inside the volcano is blown apart by the rapid expansion of hot volcanic gases.
Magma explodes as the gas dissolved in it comes out of solution as the pressure decreases when it flows to the surface. These violent explosions produce solid chunks of material that can fly from the volcano. Chunks smaller than 2 mm in diameter are called volcanic ash. Among the loose beds of ash that cover the slopes of many volcanoes, three classes of materials are represented. In addition to true ashes of the kind described above, lumps of the old lavas and tuffs form the walls of the crater, which have been torn away by the violent outbursts of steam, pieces of sedimentary rocks from the deeper parts of the volcano that were dislodged by the rising lava and are intensely baked and recrystallized by the heat to which they have been subjected. In some great volcanic explosions, nothing but lumps of the old lavas and tuffs forming the walls of the crater etc. were emitted, as at Mount Bandai in Japan in 1888. Many eruptions have occurred in which the quantity of broken sedimentary rocks that mingled with the ash is great.
In the Scottish coalfields, some old volcanoes are plugged with masses consisting of sedimentary debris. These accessory or adventitious materials, however, as distinguished from the true ashes, tend to occur in angular fragments, when they form a large part of the mass, the rock is more properly a "volcanic breccia" than a tuff; the ashes vary in size from large blocks 20 ft or more in diameter to the minutest impalpable dust. The large masses are called "volcanic bombs". Many of them have ribbed or nodular surfaces, sometimes they have a crust intersected by many cracks like the surface of a loaf of bread. Any ash in which they are abundant is called an agglomerate. In those layers and beds of tuff that have been spread out over considerable tracts of land and which are most encountered among the sedimentary rocks, smaller fragments preponderate and bombs more than a few inches in diameter may be absent altogether. A tuff of recent origin is loose and incoherent, but the older tuffs have been, in most cases, cemented together by pressure and the action of infiltrating water, making rocks which, while not hard, are strong enough to be extensively used for building purposes.
If they have accumulated subaerially, like the ash beds found on Mt. Etna or Vesuvius at the present day, tuffs consist wholly of volcanic materials of different degrees of fineness with pieces of wood and vegetable matter, land shells, etc. but many volcanoes stand near the sea, the ashes cast out by them are mingled with the sediments that are gathering at the bottom of the waters. In this way, ashy muds, sands, or in some cases ashy limestones are being formed. Most of the tuffs found in the older formations contain admixtures of clay and sometimes fossil shells, which prove that they were beds spread out under water. During some volcanic eruptions, a layer of ashes several feet in thickness is deposited over a considerable area, but such beds thin out as the distance from the crater increases, ash deposits covering many square miles are very thin; the showers of ashes follow one another after longer or shorter intervals, hence thick masses of tuff, whether of subaerial or of marine origin, have a stratified character.
The coarsest materials or agglomerates show this least distinctly. Apart from adventitious material, such as fragments of the older rocks, pieces of trees, etc. the contents of an ash deposit may be described as consisting of more or less crystalline igneous rocks. If the lava within the crater has been at such a temperature that solidification has commenced, crystals are present, they may be of considerable size like the grey, rounded leucite crystals found on the sides of Vesuvius. Many of these are perfect and rich in faces because they grew in a medium, liquid and not viscous. Good crystals of augite and olivi
Caesarea Maritima known as Caesarea Palestinae, was an ancient city in the Sharon plain on the coast of the Mediterranean, now in ruins and included in an Israeli national park. The city and harbour were built under Herod the Great during c. 22–10 BC near the site of a former Phoenician naval station known as Stratonos pyrgos named after the 4th century BC king of Sidon Strato I. It became the provincial capital of Roman Judea, Roman Syria Palaestina and Byzantine Palaestina Prima provinces; the city was populated throughout the 1st to 6th centuries AD and became an important early center of Christianity during the Byzantine period, but was abandoned following the Muslim conquest of 640. It was re-fortified by the Crusaders, slighted by the Mamluks in 1265; the name Caesarea was adopted into Arabic as Qaysaria قيسارية. The location was all but abandoned in 1800, it was re-developed into a fishing village by Bosniak Muslim immigrants after 1884, into a modern town after 1940, incorporated in 1977 as the municipality of Caesarea within Israel's Haifa District, about halfway between the cities of Tel Aviv and Haifa.
The ruins of the ancient city, on the coast about 2 km south of modern Caesarea, were excavated in the 1950s and 1960s and the site was incorporated into the new Caesarea National Park in 2011. The site of the former Phoenician naval station was awarded to Herod the Great in 30 BC. Herod built his palace on a promontory jutting out into the sea, with a decorative pool surrounded by stoas, he went on to build a city, which he named in honour of his patron Caesar Augustus. In the year AD 6, Caesarea became the civilian and military capital of Iudaea Province and the official residence of the Roman procurator Antonius Felix, prefect Pontius Pilatus; this city is the location of the 1961 discovery of the Pilate Stone, the only archaeological item that mentions the Roman prefect Pontius Pilate, by whose order Jesus was crucified. It is that Pilate used it as a base, only went to Jerusalem when needed; the city was described in detail by the 1st-century Roman Jewish historian Flavius Josephus. Josephus describes the harbor as being as large as the one at the major harbor of Athens.
Remains of the principal buildings erected by Herod and the medieval town are still visible today, including the city walls, the castle and a Crusader cathedral and church. Caesarea grew becoming the largest city in Judea, with an estimated population of 125,000 over an urban area of 3.7 square kilometres. According to Josephus, Caesarea was the scene in AD 26 of a major act of civil disobedience to protest against Pilate's order to plant eagle standards on the Temple Mount of Jerusalem; the emperor Vespasian raised its status to that of a Colonia, with the name Colonia Prima Flavia Augusta Caesarea. According to Josephus, the outbreak of the Jewish revolt of AD 66 was provoked by Greeks of a certain merchant house in Caesarea sacrificing birds in front of a local synagogue. In AD 70, after the Jewish revolt was suppressed, games were held here to celebrate the victory of Titus. Many Jewish captives were brought to Caesarea Maritima. After the destruction of Jerusalem in AD 70, Caesarea became the provincial capital of the Judaea Province, before the change of name to Syria Palaestina in 135, in the aftermath of the Bar Kokhba revolt.
Caesarea was one of four Roman colonies for veterans in the Syria-Phoenicia region. Caesarea is mentioned with respect to its non-Jewish population; when it was built in the 1st century BC, Sebastos Harbor ranked as the largest artificial harbor built in the open sea, enclosing around 100,000 m2. King Herod built the two jetties of the harbor between 22 and 15 BC, in 10/9 BC he dedicated the city and harbor to Caesar; the pace of construction was impressive considering complexity. The breakwaters were made of lime and pozzolana, a type of volcanic ash, set into an underwater concrete. Herod imported over 24,000 m3 pozzolana from Pozzuoli, Italy, to construct the two breakwaters: the 500 meter long on the south and the 275 meter long on the north. A shipment of this size would have required at least 44 shiploads of 400 tons each. Herod had 12,000 m3 of kurkar quarried to make rubble and 12,000 m3 of slaked lime mixed with the pozzolana. Architects had to devise a way to lay the wooden forms for the placement of concrete underwater.
One technique was to drive stakes into the ground to make a box and fill it with pozzolana concrete bit by bit. However, this method required many divers to hammer the planks to the stakes underwater and large quantities of pozzolana were necessary. Another technique was a double planking method used in the northern breakwater. On land, carpenters would construct a box with beams and frames on the inside and a watertight, double-planked wall on the outside; this double wall was built with a 23 cm gap between the outer layer. Although the box had no bottom, it was buoyant enough to float out to sea because of the watertight space between the inner and outer walls. Once it was floated into position, pozzolana was poured into the gap between the walls and the box would sink into place on the seafloor and be staked down in the corners; the flooded inside area was filled by divers bit by bit with pozzolana-lime mortar and kurkar rubble until it rose above sea level. On the southern breakwater, barge construction was used.
The southern side of Sebastos was much more exposed than the northern side, requiring sturdier breakwaters