Geophysical Survey

Over the last two weeks we have been very busy carrying out the second phase of the investigations at Brockhampton. A series of geophysical surveys using different techniques and technologies have been employed.  These consisted of a magnetometer survey, ground penetrating radar and a resistivity survey.

The magnetometer survey carried out by Stratascan covered an area of 11.21 Hectares (27.71 Acres), an area that extended from the house and chapel site, through the orchard to the north and beyond.

The area surveyed using the magnetometer shown on the 1829 Estate Map of Brockhampton
The area surveyed using the magnetometer shown on the 1829 Estate Map of Brockhampton
Magnetometer in use to the north of the house and orchard
Magnetometer in use to the north of the house and orchard

Much like a metal detector, a magnetometer identifies concentrations of iron oxides within the ground.  No only is it good at picking up buried iron objects, but also hearths, pits, ditches and areas of representing burning.

Stratascan was also commissioned by the National Trust to carry out a survey using ground penetrating radar around the chapel and house.  Unlike the magnetometer survey, ground penetrating radar or GPR, provides us with a cross-section of the ground beneath us, indicating the location and depth of buried features such as floors, walls and pits.

Ground Penetrating Radar employed within the grounds of the Lower Brockhampton House
Ground Penetrating Radar employed within the grounds of the Lower Brockhampton House

You will have to wait for Stratascan’s results however, as a good deal of processing is required.  But we won’t have to wait too long, as it will all be ready for the next events weekend on the 6th & 7th June 2015.

Stratascan are not the only ones to have had all of the geophysical fun! So have the pupils of St Peters Primary in Bromyard; Suckley Primary School; individuals from Mind; ECHO; Bromyard and District Local History Society and the visitors to the Brockhampton Estate.

In all almost 400 hundred people have participated in a resistivity survey of the grounds to the front and rear of the ruined chapel.  The survey in effect measures the moisture content of the ground beneath us by passing a low electric pulse into the earth and measuring the level of resistance it receives.

Resistance survey to the rear of the chapel
Resistance survey to the rear of the chapel

11241615_1066908490004798_6697153216074181159_oIf there is a high level of resistance in the soil, there is less moisture.    This can be due to there being some underlying buried floors, walls, rubble or natural bedrock.  If there is a low level of resistance to the current, then there is more moisture, perhaps due the presence of underlying buried pits or ditches.  Much like the other two surveys however, you will have to wait for the results.

 

 

Watch this space and join us at Lower Brockhampton on the 6th, 7th, 13th and 14th June to find out the results and help us decide on where to plan our summer of excavations.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s