The term strewnfield indicates the area where meteorite

Meteorite

A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

s from a single fall are dispersed.
It is also often used with tektite

Tektite

Tektites are natural glass rocks up to a few centimeters in size, which most scientists argue were formed by the impact of large meteorites on Earth's surface. Tektites are typically black or olive-green, and their shape varies from rounded to irregular.Tektites are among the "driest" rocks, with...

s produced by large meteorite impact.

Formation

There are two strewnfield formation mechanisms:

1. Mid-air fragmentation: when a large meteoroid
   Meteoroid
   A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth's atmosphere is called a meteor, or colloquially a shooting star or falling star. If a meteoroid reaches the ground and survives impact, then it is called a meteorite...
   
    enters the atmosphere
   Atmosphere
   An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
   
    it often fragments into many pieces before touching the ground due to thermal shock. This mid-air explosion causes the dispersion of the material over a large oval-shaped area. The orientation of this oval is determined by the flight path of the meteoroid. When multiple-explosions occur, the material can be found in several overlapping ovals.
2. Impact fragmentation: when there is almost no mid-air fragmentation the fragmentation can occur upon impact. In this case the strewnfield shape can be different, usually circular. (e.g. Canyon Diablo
   Canyon Diablo (canyon)
   Canyon Diablo is a canyon north of Two Guns in Northern Arizona. It is located in the Navajo Indian Reservation.The canyon passes three miles west of Meteor Crater. The community of Canyon Diablo, Arizona on the edge of the canyon about 12 miles northwest of the crater was the closest community...
   
    at Meteor Crater
   Meteor Crater
   Meteor Crater is a meteorite impact crater located approximately east of Flagstaff, near Winslow in the northern Arizona desert of the United States. Because the US Department of the Interior Division of Names commonly recognizes names of natural features derived from the nearest post office, the...
   
   )

Fragments distribution

In the case of mid-air fragmentation, smaller fragments tend to fall shorter. That is why the biggest fragment is usually found at one end of the oval. In order to get an idea of the original flight direction it is necessary to analyze the size pattern of the material over the strewnfield.